[q3]

Just say "Sir, I have given you an argument, I am not obliged to give you an understanding" and then hop out the window.

[Brian_K_White]

Disappointed that this wasn't Feynman. However thank you for bringing it to my attention.

My unequal trade,

"The rain, it raineth on the just, And also on the unjust fella, But chiefly on the just, because, The unjust steals the just's umbrella."

edit: I was obviously thinking of "I can only explain it to you. I can't understand it for you." but that appears not to be Feynman either. Oh well!