I wouldn't say I've unlearned anything. (Maybe forgotten a few things...)
I still use algorithms that were useful in C and Info/Basic, but some of the statements are rearranged. The biggest difference is just the way for(each) loops are done.
The second is how to avoid using ! and using unless instead of if in appropriate situations.

The only things to unlearn are bad practices. Good coding shouldn't have to be unlearned.