1. That time when he attempted to flirt with a lady who was also stuck in an ATM vestibule.
"You know on second thought, gum would be perfection!"
Could have said 'gum would be nice, I'll have a stick'. But oh no, for me, gum is 'perfection'.
2. The time(s) when he gets back with Janice...AGAIN
"OH. MY. GOD!"
3. When he lost it at Ross for telling him to 'pivot' a couch they were moving.
Ross: "Pivot, pivot, PIVOT!"
Chandler: "Shut up, shut up, shut UUUPP!"
4. ANY time he had a bromance moment with Joey.
5. When Ross caught Chandler celebrating like THIS...
6. When Chandler does some thinking out loud...
7. When Chandler is reeeaallly excited about partying with his college friend Gandalf.
8. When he shares this very awkward kiss with Phoebe, then announces his love for Monica
Chandler: Come here. I'm very happy we gonna have all the sex...
Chandler: OK, OK, YOU WIN! I can't have sex with you!
Phoebe: *Delighted* "And why not?
Chandler: Because I'm in love with Monica!
9. When Chandler FINALLY proposes to Monica...and she gets down on one knee
"You make me happier than I ever thought I could be."
10. The times he couldn't BE any funnier (which is always)