Which pets-related expansion pack do you like most?

I have played the pets versions from Sims 2 to Sims 4. I loved them all for different reasons, even though I don't own my first pet stuff.
I chose sims 2 for pets, because my pets could get jobs, and each promotion unlocked coat colors and patterns. I also went with it, because I was playing it one time, and had two cats go outside to a doghouse where they would get together. My Sims inside the house ran out of the house to cheer them on, so I am entirely biased due to that.