I thought about naming a few but then i realized they are never funny for like 90% of people here who would rather live in the world without laughter lol ...
Once at a table in vegas.
Him: "Ha, I got your set beat with a straight!" as he slams his cards down on the table
Me: "Last I knew, you needed 5 cards to make a straight" as we all see he's a card short of one...
He not only lost the hand, he just quietly got up and left the table after we all had a good laugh.
Not quite what you were looking for, but I'll always laugh remembering it at least!
I remember my brick-and-mortar days when I had the Blind and only one other player limped in. My usual reply was, "Ah, just me and the winner left." Usually got some laughs.
When I was in Vegas a guy raised and the other guy folded and the raiser said "I would tip you dealer but you didn't give me the best hand" great bluff reveal.