On the news this morning I listened to a report about a new virus discovered in Saudi Arabia. But after talking about how scary and disturbing that is, it was mentioned that it has infected a total of two people and is believed to be only transmissable from non-human animals to humans, so it probably won't be any significant threat to the tens of thousands of people expected to flood into the country for the Hajj, the pilgrimmage to Mecca.
And I thought.....man, I'm glad I don't believe in a god who wants me to do things.
Not just things like go on a pilgrimmage to a country where I might get infected with a virus, but anything. Because those things might be against my own interests, and because they're expectations of a god, they're not expectations I could advisably ignore.
Now, morality requires you to act against your own interests sometimes-- only psychopaths go around using other people with absolutely no regard for those peoples' welfare. But with morality, you're refraining from harming people for the sake of those people. With the expectations of a god, you're refraining from doing things because of the demands of a being that you don't even know exists. And whom you can't harm.
Frequently, and happily, the expectations of the gods people believe in just happen to be things they would do anyway, because they're also moral (e.g. giving to the poor). Infrequently, the expectations of the gods people believe in are very immoral indeed (e.g. punishing non-believers). And frequently those expectations are morally neutral or close to it (e.g. making a pilgrimmage). But even a morally neutral expectation can be an unnecessary pain in the ass at best for the believer because it still requires him or her to at least exert some energy, time, and/or money on something he/she wouldn't otherwise do. And in this case, could actually prove very harmful to him or her.
Good things are worth doing because they're good.
Good things may be good because of God, or they may not. But regardless, you don't need to believe in God to know what Good is, and to do good things.
If God is good, then God should only expect us to do good things. Not bad things, and not neutral things. Not because neutral is bad, but because it's subjective-- once you demand that someone do a neutral thing rather than them doing it for their own pleasure, you're imposing on them. And that's bad.
Therefore, it would be reasonable for a believer in God to do only those things which God expects that are recognizable as good by the believer him/herself. Which would mean that "God says so" is never sufficient reason to consider something good.
Therefore, a believer who is moral should behave identically* to a non-believer who is moral.
Therefore, you can tell if the god someone believes in is good by whether that person's behavior reflects an expectation of doing only Good things, not bad things or neutral things.
Therefore, believing in God, if God is good, is a morally neutral thing to do. As is not believing in God. If God is bad or neutral, then believing in God is an imprudent (bad for you) or bad (immoral) thing to do.
*Edit: This is a problematic term. I don't mean "exactly the same as" but "indistinguishably from."