Do you ever write any LISP extensions to the IDE?

I've written some simple modes and have extensively modified the way some commands work.

Small example ... the GNUS new browser used F for followup (to the newsgroup) and R for reply (email the author), and I habitually pressed the wrong key.

So I wrote a small function that would query "Do you want to post a message or email a reply?" to the user and then do the right thing. Although I occasionally still answer the question wrong, it has eliminated most of my posting errors.

My emacs startup files contain nearly 3000 lines, accumulated over the years.