People, over the years, have wasted a great deal of effort debating the existence of God, or gods. Through most of history, this was either a "my god is stronger than your god" or a "your god doesn't exist but mine does" type of argument. Science has replaced this with a "no gods exist" argument. Well, to be correct, the argument is "no gods need exist." The distinction is important.
By way of example, suppose someone said to you "cars are powered by hamsters running in a wheel under the hood." Now, you may disagree. You may go so far as to prove your argument by opening the hood and showing this person that, indeed, there is no hamster running in a wheel there. But, what have you proven? Have you proven that hamsters don't exist? Well, no. Have you proven that no cars are powered by hamsters? No, you've just proven that this car is not. You've proven that it's possible for a car to be powered by a mechanical engine and not a hamster. You've proven that you don't need hamsters to power cars. This is what science has been doing for years and years.
Science has slowly chipped away at the god-powered world. It has, one step at a time, proven that phenomenon, once thought to be the will of God or gods, is actually capable of happening by natural means. Science has been so successful with this that a reasonable person may now conclude that, while some phenomenon are not yet understood, there is no reason to believe that any god is necessary for the world to function as observed. Some would argue that because the world can function without God, God does not exist. However, this argument doesn't work; after all, hamsters exist.
In fact, outside of mutually-exclusive categories like married bachelors, you can never prove that something does not exist. You can prove that something does not exist in a defined space and time, there is no hamster under this hood right now, but you cannot prove that something does not exist anywhere at any time, hamsters may exist somewhere, sometime. Now, you can replace 'hamsters' with just about anything. Most anything can possibly exist, somewhere, at some time. This is especially true for something as ambiguous as a god, something that can't be seen, something that is everywhere yet nowhere. You can prove that God is unnecessary, but you can't prove that God does not exist.
Thus, given that no one has ever proven that any god exists but it is impossible to disprove the existence of a god, any reasonable person would reach the conclusion that they don't know if any particular god exists or not. At this level, the Agnostic has the only defensible position. So, what are people debating about? Well, they are arguing about beliefs; two kinds of beliefs, to be precise. One type of belief is what's already been covered here: The belief that some phenomenon is powered by a god. It is perfectly rational to argue for and against these arguments, so long as both parties acknowledge that proving said phenomenon can occur without a god's intervention does not disprove the existence of said god, or that said phenomenon could not be powered by a god somewhere, sometime, but not always. The second kind of belief is the belief in existence, without proof. A rational person may chose to believe that the existence of something is highly unlikely; they may chose to place God in the same category as Bigfoot, goblins, and elves. However, it is also entirely rational to chose to make a leap of faith and believe in the existence of something without any proof. Everyone does it all the time; people can't possibly have everything proven to them. Some things you just have to accept and get on with life. Debating about the likelihood of a god existing may be interesting, but it won't get you anywhere. What a person choses to believe, without proof, is a very personal thing.
However, there is another argument that most people overlook: is it reasonable to worship a god? People usually conflate belief with worship. They don't ask "do you worship God," they ask "do you believe in God," thinking belief automatically leads to worship. It doesn't. Believing in the existence of something does not necessarily lead to worship. People can believe in the existence of hamsters without worshiping them. People can believe in the Devil without this leading to worship. It is not necessary to prove that something does not exist before proving that worshiping that thing is wrong.
For example, we can posit the argument, illustrated below, that there are no good reasons to worship God and there are good reasons not to. This argument holds irrespective of the existence of God. If the existence of God was irrefutably proven, beyond doubt, this would still not change the argument.
Worshiping God is the wrong thing to do. Why worship God?
Because he is the Creator? So? Your parents created you; should you worship them? Honor perhaps, but worship? If a man creates a sentient computer, should the computer be obligated to worship the man?
Because he can bestow good fortune? Well, statistically, this theory is pretty much debunked. If you still think this is true, then you should read up on "confirmation bias" because, well, you've got it. Being a member of a religious order that supports their own members may bring good fortune; following proscribed religious rules may help you make good life-choices. But, praying to God isn't going to do much more than meditating on your problems without invoking God. You're better off praying to your toaster; at least you can reasonably expect toast.
Because if you don't you're soul will burn in Hell? Anyone care to look up the term 'extortion'? If you worship for fear of being punished then you are a coward. Humans have laws against extortion for a reason, it's morally wrong. A moral argument can be made for using the threat of punishment to enforce mutually beneficial social rules, paying your taxes for example, but none can be made for worship. If an almighty Creator made a universe where failure to worship Him results in eternal damnation, then a morally courageously person would have no choice but to chose Hell. That god is evil and worshiping it is morally wrong.
Because you want to spend eternity in Heaven? Define Heaven, go ahead. Anyone that truly considers the nature of Heaven, beyond "basking in the Love of God," will soon realise that it simply won't work. Humans are finite beings, there is no eternal existence that would not, eventually, become insufferably boring. Imagine anything you love to do; now imagine doing it for billions and billions of years, over and over and over again. Maybe, a few extra lifetimes spent debating with the great minds of history, being with loved ones, or doing something your really love may be great. But, nothing, no matter how enjoyable, will survive the onslaught of boredom, given sufficient time, nothing. Any definition of Heaven, multiplied by eternity, equals Hell.
Still, even if there is no good reason to do something, it does not follow that people should not do it. Why not worship God?
Because worshiping God has, time and time again, led people to bigotry and hatred of other people. Any review of history will show many, many examples where worship of God has justified murder, wars, and other morally wrong actions. You may feel that there are many examples where the worship of God has brought people together, helped overcome bigotry and hatred. Yes, there are examples of people coming together under the banner of God. Unfortunately, history has shown, time and time again, that those people are likely to then go off and kill some other group with a different god.
Because worshiping God will distract people from making improvements in their lives. If God helps those that help themselves, why not dispense with God and just get done what needs doing. After all, why waste effort praying to a god that has not, in a statistically proven way, given any measurable help to those who pray?
There are no good reasons to worship God and there are at least a couple of decent arguments against worshiping. Worshiping God may lead to aggression against people who worship differently, or it may simply be a waste of time. This cost may be tolerable if there were counteracting positive reasons, but there are none. Worshiping God provides no benefits but may lead people to morally wrong other people. Thus, a reasonable person would chose to not worship, irrespective of any belief in existence. People generally chose to not worship the Devil, why should they chose to worship God?
The above argument, while admittedly simplistic and weak, illustrates the original point. People have been arguing about the existence of God, or gods, for a very, very long time. Those arguments have not and are not going to get anywhere. However, by changing the argument to "should people worship God, or gods," a lot can happen. Costs and benefits can be raised, moral issues discussed, and conclusions reached. We cannot make any definitive conclusions about the existence of a god, but we can conclude whether or not that god should be worshiped.