Let me re-arrange your sentences: 1. I think if I waited long enough, I wouldn't need to take a haircut. 2. People must either think that it (a puzzle) is a waste of their time or they must not be interested at all. 3. I would appreciate if you mind your own business.
1. I think if I wait long enough, I wouldn't won't need to take a haircut. You can "get a haircut", but you can't "take a haircut". Here you don't need either verb. 2. People must either think that it (a puzzle) is too dumb for their time or they m