Biggest sins - that's tough, there've been so many. My first Perl job was just one sin after another - probably the biggest was deciding that MySQL couldn't support the awesome search interface I was building so I would have to construct my own search database using DB files. From a certain perspective HTML::Template was a sin, although in my defense it wasn't my idea and I tried hard to redeem myself by making it useful for other people. Inline::Guile is pure sin.

Biggest pitfalls, that's an easy one. At my current job we don't use a CMS - instead every commit to SVN goes lives immediately and everyone (and I do mean everyone, not just coders) makes commits to SVN. Oh, and about half the code is copy-and-pasted Mason! Oddly enough, it's still a great job.

Runner-up would be the job where I did design and code review for 10 programmers in India. I couldn't actually talk to them, I could only talk to their managers. And I didn't actually have any power over them at all, despite the fact that a few of them obviously couldn't code. And I didn't get to go to India to visit them and travel the countryside. (I'm still bitter about that last one - I was all set to go, had my visa in hand when the trip was cancelled.)

-sam