A rhetorical question asked to show that the person asking it neither knows the answer nor would be able to know it.

An offering of assistance. / An indignant response to nosey or rude behavior.

Alternative form of if I do say so myself

(literally) As I last remember; last I recall. / (figuratively) Yes; affirmative; obviously.

(literally) Used to indicate that a certain expression, custom, etc. is characteristic of the speaker's place of origin. / (humorous) Used to indicate that a certain conclusion should be obvious.

Alternative form of that's what I call

Impolite demands are not conducive to getting what one wants.

Used to show that the speaker hates or strongly dreads the task in question.

Alternative form of dot the i's and cross the t's

(informal, idiomatic) Indicating that one is serious and not joking about a matter.