[Serious] Why are you an Atheist?

[EgoDeath]

Are you just going to keep asking questions? Are you working towards some elaborate "Comforting" gotcha moment?

Anyhow, I have so much work to do, I'll have time to construct ethics when I'm dead, which answers both your questions. But seriously, personal ethics are considerations rooted in basic values, and I got those probably in equal parts from being human and thus wired accordingly, and my upbringing and cultural background.
When I'm dead, my thoughts and memories will be lost in time like tears in the rain, and all the parts my wife doesn't want to keep will be donated to science. Says so on the card in my wallet.

OP claims that they are conducting interviews as part of a school project or something. It's at least worth considering that they don't have some sort of 'gotcha agenda.'

edit: It's also worth noting, to the OP, that I, and most others, so far as I know, are atheists simply because we do not hold a belief in any god(s). It's truly that simple, and for the most part, your questions have little to nothing to do with atheism in and of itself.