It's rude to come over without permission.
Rudy is feeling lonely and misses his friends.
Rudy wants to hang out with his friend Fred.
Rudy calls Fred to ask if he wants to hang out later.
Rudy stops by Fred's house to socialize with him.
Rudy and Fred go out for dinner and drinks and have a great time.
Fred is surprised and irritated that his friend came over unannounced.