I don't condone cruelty either virtually or in RL. I never choose the 'Yell At' option, even when my Sims' children full-on deserve a 'dressing down'. I have learned through experience that yelling, just like swearing, is the act of a lazy mind trying to express itself forcibly. It really is a useless practice as you almost never get anywhere with the Sim, person, or animal. Sometimes using a whisper or a more quiet attitude goes farther.
I haven't yet purchased the My First Pet pack. I've been thinking a lot about taking the plunge, as it were, but I am bothered by your complaints. I wanted small pets in my game. My Rock Star in Sims3 had a large bird, for instance. Personally, I love birds. I read somewhere that having pets in the game can cause problems regarding some of the mods I use, so I don't have pets. Plus having them takes up a slot in our already very limited households. Why? I did get my Sims' kids the large fish tank. But, alas, unlike the one in Sims 3, it's totally unnecessary to even feed them, let alone clean the tank. Face/palm. Somebody please tell me what is the point?
