[mechanical_fish]

A: Anything you have to do by hand up to 400+ times is not particularly easy. It's an hour's mind-numbing work.

B: It's only easy if there's no cognitive load to unfriending someone. If you have to call them up in your mind, decide if they're still a friend... that's thought, and the emotions involved can be literally overwhelming depending on your personality.

C: Do the people you unfriend get alerted in any way? Take everything I alluded to in point B and raise it to the third power, because now every click is also a social signal...

[falling]

A: True, but “mind-numbing” does not mean “quite difficult”. Also, if you have 400+ Facebook friends you wish you hadn’t I think it’s your fault, not Facebook’s. I don’t expect any service to provide marginal functionality like that. You do that once and from then on you think more carefully before accepting someone’s request.

B: True, but the parent was talking about UI.

C: No.