I could play without mods, but would I want to... absolutely not! For me, the game just would not be enjoyable without mods... especially the small mods I use to fix bugs or change design choices I hate.
I want to make my own townies and have no random NPCs generated... Need a mod for that because the game doesn't allow me to control NPC generation.
I hate situational outfits! Well, need a mod to disable that annoying feature.
Why is this random person from the opposite side of the map trying to join my private conversation and making my sims stand around like idiots waiting for him to walk up to us? Well, need a mod to prevent that from happening.
Sure, it's a pain sometimes to update them all after a patch, but it's worth it because mods make me happy.