You're missing out on some of the best Star Wars has to offer, then. :/
They may be cartoons, but they're as good if not better than any of the movies. The Clone Wars in particular redeems the prequel films and makes me feel for Anakin, Ben, the clones, etc. Vader doesn't feel like a forgone conclusion, but a villain created from a very conflicted young man who had one bad day when he was 19 and then years of heroism as the best star pilot in the galaxy, and a cunning warrior. And he was a good friend.
We see his two worst weeks in II and III. TCW shows everything in between, when he's at his best down to near his worst, before his turn to the Dark Side. We see why Padmé and Luke say that there's still good in him. We see why Ben calls him his brother. We don't see that in the movies because The Clone Wars is too large a story to tackle in just 2 films.
You can easily skip much of the series, but there are some really good arcs I'd URGE you to watch, despite their cartoon appearance.