In all seriousness, what is the most useful superpower? I would say...

...that the most useful superpower would be that of:

20/20 Foresight

Why? Every time you must ask yourself "is this the right choice?" you will know if it is or not. Think about it, you'd be ahead of this game called life. This is different from knowing the future because in this case it is not fate but rather multiple possibilities thought out in perfect simulation before brought into reality.

Thoughts?