'would have' or 'would of'?

[PollyA]

I think its one of those strange language things, not necessarily laziness. If you say would've or should've outloud they really sound like would of and should of, and since language is taught verbally much more than written, its just been "adapted" over time.
In saying that, "of" isn't correct, The word should is an auxillary verb indictaing obligation to carry out the verb that follows. Of is not a verb and therefore "should of" just doesn't work gramatically
"Of" is a preposition not a verb.

On a completely different note, the words should and would are not very helpful in many ways. I spoke to counsellor the other day who works with young people dying of terminal illness, usually cancer. His colleague has a poster he gives to his clients which reads "I will not should myself today". Sometimes the "shoulds" expressed on the forum get me down too. Especially in terms of parenting which has a million different answers and rarely any definites with a couple of exceptions like "You should not put coke in a baby's bottle" Anyway very philosophical thism morning.

You should use have lol!