believe it or not, i used to do cocaine (not crack, never tried that) recreationally, and never had a problem. i liked it, but didn't spend any money on it (boyfriend did that), when it was gone, it was gone, never craved it, etc.
some people are just wired differently than others.
give me a pill, any pill, and i'm immediately hooked
BUT, better safe than sorry. i wish people wouldn't even try it once