How come there isn't a "let your opponent have his last move back button?"

I was recently playing a good game, about to get into an exciting end game when my opponent made a disastrous move.  I definitely would have allowed him to take the move back otb just so we could have had a proper and exciting endgame.

i think take back games allow that im not sure

I tend to agree, although then technically it's not chess since the rules call for touch move.  Perhaps there could be a separate area for "friendly"
 games that allow for taking back a move...

I play at my office and my mouse gets stuck and were ever it sticks you have to re click and it will drop were ever it got stuck that suck and I dont think my boss will buy another mouse so I can play chess so I m for take back

Can you play take-back on live chess?  I have seen it in regular correspondence chess.

These are all friendly games.  Besides, you would always have the option of not allowing "takebacks" were you so inclined.

I would never allow a "take-back" you learn from your blunders.

Agreed . . . no "take-backs"--learn from your mistake.

C'mon man!  How many times have you allowed me to retract a move over the board?