ALL-TIME BEST BAD REACTIONS TO A CARICATURE:

These are all real, true-life-story comments from real customers. 
They are all recent, and I'll continue to add to the list as those 'stellar' reactions continue.

“This SUCKS! YOU suck!” (2BW: Boyfriend paid)

“You would get better tips if you didn’t draw so terribly, and if you weren’t such a horrible person.” (4BW: Friends loved it and paid)

[Random passerby]: “Don’t you buy that! Don’t you buy that! Shame on you, artist! SHAME ON YOU!” (She loved it and paid for it.)

“I don’t look like this! (To a random passerby): “Does THIS look like me?” [Passerby]: “Yeah, it looks just like you!” (That was not what she wanted to hear!) (Friend paid)

“I’m not like that… I’m pretty!” (2BW: Reject)

“He’s not the pretty one! I’M the pretty one!” (2BW: Boyfriend paid)

“Look at me! Durrr! DUUURRRR!!!!” (2BW: Boyfriend paid)

“Do you expect me to pay for that?” (2C: Reject)

"Do you draw everybody as ugly as that?"
-my fellow artist and I smiled at each other, and simultaneously snapped back: "Yes!"

A new one: A stunningly beautiful girl, I drew her caricature SUPER 'cute.'
*sigh* "Ohhhhh.... I'm not pretty." (1C - paid)
:S LOL

And here is the ALL-TIME NUMBER ONE WTF? COMMENT:

“Your drawing killed my mother."

What do you mean?
"You drew my mom and she died. I’m very superstitious and I want my money back.”
Where's the drawing?
“Oh, I burned the drawing.”
No, he did not get a refund... 
But when it comes to harsh critiques, ‘your drawing killed my mother’ tops the list.