This is my ultimate 4-player card game. When you're really young, you learn how to play go-fish. Then you learn Uno. Then maybe Skip-Bo on the way to Euchre (at least in the midwest!).
This is the card game that is at the end of this long road. (perhaps along with Bridge and Spades.....although I don't really enjoy either of those as much as Tichu).
Sure, you can always have tons of cards games at your disposal; but I would say that without Tichu, you'd be missing something great.