How many folders is too many?

So I am curious, in most email client nowadays you have a crap ton of folders on the left hand side, you have "pinned/starred", "snoozed", "reply later", "important", "draft", "sent", "trash" then you have all the ones you probably made yourself. So my questions are this: 1) Which folder (if any) can't you live without? 2) Does your OCD kicks in a little bit having so many folders? 3) If you were king for a day, how would you change that?