This common confusable is more often spoken incorrectly than written but it drives me nuts nonetheless.
"I should have went to the bar last night."
Oh, come on. Seriously?
You know, of all the verbs you could get wrong, "go" shouldn't be one of them. It's one of the simplest we have.
Most people do pretty well with the present tense:
"I want to go to the store."
"He keeps going on and on about Twitter."
"He goes, like, 'Duh.' And I go, 'Uh…yuh!'"
So yes, we do pretty well with go. But that's it. That whole gone versus went part seems to elude us. Want to remember which to use? Here's how:
No other word goes with went.
"He went to the park."
"She went to the grocery story."
"They went, and then I went, to the bar and got toasted."
It's not should have went or could have went. No.
No, no, no, no, NO!
When you feel the urge to add other words (as in the past perfect tense), use gone.
"I should have gone to the park."
"I might have gone to the grocery store if I knew she was going to be there."
"I could have gone to that job interview but I slept in."
And by the way, it's should HAVE and could HAVE, not should OF and could OF.