I don't remember UNlearning anything, but there are some things about perl that took me some time to get used to them. One such thing is definitely the context -- I believe I have never previously seen a language in which the value returned by an expression depends on what you want to do with it. It's the most un-C-like feature in perl (although it's somewhat similar to functional languages' type-guessing).

Another thing is perl's idea of OO. It's strange. It's funny. It's not actually OO by most definitions of the term -- it does not even pretend to protect object's variables, for example. But it works ;-)

Last but not least there's the matter of map and grep -- for a very long time I used loops and (god forbid) indexes to convert one array into another. foreach and map are just beautiful.

The interesting part is that you don't *have* to learn these things to start programming in perl -- sooner or later they will get to you anyway ;-)

-mk