Under the influence

I found this joke online — I thought it was so funny!

A guy walks into a bar, sits down and has a drink. Suddently, a man hollers at him, “I screwed your mom last night!” Disturbed, the man tries to ignore him.

Again, he hears, “Your mom was so good in bed last night!” Again, he tries to ignore it.

The man is just about to speak again but the guy stops him and says, “Dad, go home, you’re drunk!”