Resign in very win position!!!

I am surprised for this game I played a minute ago, he is a very good player but he resigned prematurely, here is the game:
http://es.lichess.org/lDbqbU3R/black#27

Maybe he foresaw a loss many moves deep. The notation for the last move would read "resigns!" (resigns with exclam :-)
Or he was extremely low on time and couldn't possibly mate within the time left?
Another possibility is accidentally clicking the flag button. In which case I would advice everyone to have in their preferences "Confirm Resignation" toggled to Yes.

it's a casual game, so he probably felt there was no value in spending the time converting it out.

http://en.lichess.org/MJv3RbdX/black#61
This is a crazy example I had - maybe opponent thought that I had mate in 2 after Rf1 Rxf1....?

lol at #4 - that's the most ironic resignation i've ever seen.

#4 most interesting position ever.. even I was confused about that mate until I played and see its not a mate actually xD

#4 this is awesome :D

I also missed the mate in one for white

I have resigned dozens if not hundreds of times here on lichess just out of the opening ether cause I am bored or I do not care and do not want to play a middle game out (I love my openings).