Most irresponsible super power to give to humans

Higher Brain Function.

Time travel, you know we'd all fuck up the past.

The ability to go to any place at any time period, with the limited only by my imagination. If anyone were to actually be a Time Lord, a lot of things would cease to exist.

Lelouch's geass ofc, the power to control human actions can be disastrous as seen from Code Geass R2.. That power fuked the world

I think the most irresponsible power you can give people is the power of omnipresence. The ability to be anywhere at anytime could definitely fuck with people's days.

The power to make someone poop their pants on command.
Although that would be hilarious.

Flying.
I think its pretty useless. Just swinging and floating yourself around is nothing but a junk.
hahahaha

Humans will find a way to make any superpower go horribly wrong...

I'm gonna go with shape-shifting. People are horrible to begin with. Imagine what would happen if they could make themselves look like anyone else.