Atheists, tell me, a Roman Catholic: why should I become an atheist?

[Mister Agenda]

For now, I've been doing some lighter research into atheists who converted into religion. Leah Libresco for example was apparently a notable atheist blogger who converted to Catholicism as it satisfied her questions about morals, primarily. I'm not sure how common it is, but in general why do you guys think some atheists end up converting to a religion?

I think she's a typical case of an atheist converting: her fiancé' was Catholic, IIRC. Of the few cases where someone I knew to be atheist online, the only reasons for conversion they were able to articulate were emotional, usually involving a significant other.

Of the people I've run into who say they used to be atheists, almost all describe atheism differently than actual atheists do, which leads me to conclude that they think they used to be atheists because they misunderstand atheism. Their reasons they give for their previous 'atheism' tend to be stereotypical: they were angry at God (mad-at-God-ism is not atheism), they were sinners (drinking and fornicating aren't atheism), or they weren't born-again (not being 'saved' is not atheism). They say they were atheists, but most of them believed God was real during their 'atheist period'. Some will even use their belief in God as justification to claim that atheists secretly believe in God.

I'm always interested in atheist conversion stories, hoping that they'll have some kind of evidence or argument more convincing than what we usually see, but I have always been disappointed so far.