Note: I don't claim to be great at translating and I'm only just starting out. Honestly, this is just a personally kept list that I plan on regularly updating as I grow as one. But I've noticed there are a lot of expressions that are rather difficult to translate (whether due to the variety of translations available in terms of context or just a lacking equivalent) and more often than not, dictionaries are insufficient. If you have a better idea of how to translate one of the words below, tell me, cuz I'm all open to suggestions.

ふざけるな
-Don't mess with me
-you're not serious!?
-stop playing games


勝手
-selfish
-unfair
-willful

やはり/やっぱり
-I knew it
-just as I thought
-Indeed
-as suspected
-figures

お世話になって
-to be indebted
-to be in one's care