I Hate To Be A Dick - You're about to say something that makes you look like a jer

You're about to say something that makes you look like a jerk, so you say you hate to be a dick, which is just a fancy way of being a jerk.

I hate to be a dick, but I'm gonna say your math is bad.

I hate to be a dick, but I'm telling you your joke is weak.

I hate to be a dick, but I'm saying you're a total dweeb.