Regret
From TOW Chandler Can't Remember Which Sister
Chandler: Veronica. Look, it's got to be Veronica, the girl in the red skirt. I definitely stuck my tongue down her throat.
Monica: That was me.
Chandler: Look, when I've been drinking, sometimes I tend to get overly friendly, and I'm sorry.
Monica: That's okay.
Chandler regrets hurting Joey. He regrets kissing Mary Angela. He regrets opening Joey's presents (not that Joey really cared). He regrets embarrassing himself at Joey's family dinner. And apologies for all of those things tripped out of his mouth, one after the other, until he was more or less forgiven.
But his biggest regret of this whole fiasco is one he hasn't shared with anyone.
It's about Monica. And no, it's not that he kissed Monica (though he apologized for that, too, pretty sheepishly).
No, his biggest regret, by far, is that he doesn't rememberkissing Monica. He doesn't remember what she tasted like, or what she felt like in his arms, or if she kissed him back.
He's going to regret that for a very long time: one more lost opportunity in a sea of them that stretches back to his first unrequited crush on Ellen Stevens in fourth grade. But now that he thinks about it, he might be better off not remembering.
Because he's pretty sure it felt good.
So it's OK that he doesn't remember, because it's a whole lot easier to regret the possibility of something than the actuality of it. He learned that a long time ago.