While I agree that it can be boring to play only root notes, try listening to music that has no bass notes of any kind, then you will be begging for a root note. On the other end of the spectrum, Bassist Larry Graham played a single bass note for an entire song. He "spiced it up" by playing rhythmic accents (like muted notes, ghost notes) that copied what the drummer was playing.
You can spice things up more by playing the arpeggio of the chord in rhythm with the drum beat. So you see a C chord, play C E G in rhythm with the drummer. The fun is altering the order of the notes (CEG, ECG, GCE, etc) in a way that reinforces the harmony of the song. Unfortunately, it is not as easy as it looks, which is why we practice, practice, practice.