stand at attention! (military command)

(informal) you gotta be joking! you must be kidding!

shame on you

do you speak French?

after you!

you know what? (a phrase used to get someone's attention before announcing something)

(informal) speak for yourself! (expressing disagreement with an opinion expressed by another)

(informal) what can I say

I hear you say, I hear you cry, you may ask, you may say, some will ask, some will say

I beg you, I entreat you / please do, go ahead, be my guest / you're welcome (after being thanked)