What are your failures?
ilyak: My worst professional failure was adding Hibernate to my project at work.
I was charmed by their prospects, everyone reviewing it positively and quality of their docs.It turned out that I've spent more time making Hibernate do whatever I need without failing than doing everyting else. It followed the principle of most surprise: I could never guess what'd it go given a code snippet, provided all the complex machinery involved under the hood.Now I fear ORMs. Wrote my own for that project, it's primitive but does its stuff and is completely predictable.