well, I am not quite sure I agree with that definition of expert, by that standard I have been choosing the wrong doctors!
I have definately killed a few, though I could probably count them on one hand. Mostly due to not caring. I have had a few plants fall out of favor and not perform well, then perhaps start going and I do nothing to fix it. These have historically been noids or super common dime a dozen type hybrids that had they survived would have been given away by now anyways. Although I have had a compot of Den senile go while in my possesion. To be fair these were the runts of the flask that a friend gave me because they were not worth his time to pot up.