User can stop people doing stupid sh** before it happens.

Pros:
-user can stop people from getting hurt
-user can suggest less stupid actions
-user can share knowledge to help
-user will always be the sensible one

Cons:
-user may be called "mum friend"
-user will get annoyed quickly
-user will need cool down periods
-user can sense when something stupid is about to happen

Weakness: unknown

(Pretty sure about 80% of the anime wouldn't happen with this kind of quirk being around)