Things I've learned from being a Perl programmer that I didn't know before but can apply outside the Perl domain:

• That post-processed source can give you excellent documentation which still lives near the code.
• To see somewhat high-level concepts such as strings, regexen, lists and hashes as natural solutions to certain kinds of problems.
• Unix thinking.
• That tests are extremely useful and it's the right thing to do.
• That a quick edit-compile-run cycle makes a difference.
• That dynamic languages give you more and different things than static languages.
• To view re-use as a very natural thing.
• That efficient syntax matters when it comes to readbilit and maintainability.

/J