Neologist

One word I really always want is a nice simple word meaning the opposite of "favorite".
"Least favorite" is weak, "most hated" is awkward. I want something that's instantly understood.

Another one I need is a single word to express one's envie de pisser as it were. We have good solid words to express other physical needs: thirsty, hungry, even--ahem--horny. Peey? Weey? "Pissy" being already spoken for.