The Cunninghams are close and supportive of each other and their extended family (including Fonzie). Most of their problems are mild (the kind that are neatly solved within a half-hour episode). That said, the show does tend to reinforce the idealistic (and unrealistic) way we tend to view the '50s.
The friends get into benign, almost-simulated fistfights from time to time. In later seasons, Richie joins the army.
Plenty of dating and flirting, but it's all really tame.