Mine is "of." Somebody here did that just recently.
"OF" IS NOT A VERB!!!!!!!!!!!
should of, would of, etc.
I really get annoyed by things like "we should of went"
Then again, the thing about language is that it changes all the time, and it's a product of the people who speak it. I'll bet some day in the distant future "your" will mean "you are" and "of" will mean "have." Verb conjugation will be greatly simplified, and all these misconjugated irregular verbs like "blowed" and "knowed" will be normalized.
It will be appalling.
Still, the *vast* majority of people don't know any better, and a good case can be made that many of these things I've mentioned are already a /de facto/ part of vernacular American English.