Religious people are less hedonistic: When I became an atheist in my early 20s, I saw a change in my general outlook. Before, I had always thought in terms of doing the right thing. Even though my family was conservative, I was convinced by liberalism because it seemed the most moral.
After losing my faith, I began to see life not as a place to be good, but as a place offering nothing valuable but pleasure. If I had an ambitious personality or a strong need for money, I might have seen achievement or economic success as the goal to live for. But for me, a life of simple comfort was the best you could do. Instead of respecting some principle, it made sense to me for the atheist to follow his personality, even if his personality sucked.
Of course, it's not rational to be a short-term pleasure seeker, because if you were in every way, your life would quickly be ruined. But I could never convince myself to be a perfect long-term hedonist. The psychology of "take it easy" was too powerful. It would be easy to argue that much of my train of thought described above was not rational; much of it, indeed, was driven by the interaction between thinking and personality.
But was this experience limited to just me? I have been called an oddball more than once, I assure you.
The Longitudinal Study of Violence Against Women asked male college students how much they agreed with, "I often do whatever brings me pleasure here and now, even at the cost of some distant goal." Answers ranged from 1 for "strongly disagree" to 4 for "strongly agree." Students were also asked how much influence religion has on them.
Mean instant gratification score by influence of religion
Fair amount 1.93
Great deal 1.56
The difference between the "nones" and the "great deals" is two-thirds of a standard deviation. Looks like I'm not alone.
To the extent that outlook and values matter, I can think of few things more valuable than a culture of self-discipline. But the plot thickens: the other one that immediately popped into my head was devotion to the pursuit of truth, a commitment I think atheists can make a strong claim to.