I was watching a Friends marathon last night as I had insomnia, and thought bloody hell, Joey was actually pretty creepy the way he would pursue women with his "how YOU doin'" line and do things like take down the shower curtain when he had a female roommate and ask her sex-related questions when interviewing for a new flatmate.
And Ross was bordering on psychotic with his sandwich fixation and jealousy of just about any guy Rachel interacted with. And also that weird overprotective thing when he first found out about Monica and Chandler. She was his sister, not his possession!