I have an issue with this, too. Sims don't really notice what's going on around them. My sim and his kid were at work/school when grandma died. They came home, didn’t even realize it. I made him mourn for her and he was sad for 4 hours. He had a really good relationship with her, but since he wasn’t there to witness the death, it didn’t affect him as much.
And everyone has already pointed out the romantic issues with sims being cheated on and getting over it quickly. I don’t want to have to make sims have reactions, they should be based on traits and relationships, right?
For example, bladder failure. Other sims could laugh or be shocked like in the ts3, parents could scold kids too. Witness a fight? Maybe console the one who lost or laugh at them or scold both sims involved for fighting? Maybe these interactions are in the game and I haven’t seen them yet, but there’s only Share Big News for pregnancies…is there nothing for engagement, marriages, talk about new family member kinda stuff? Congratulate on promotion? Do sims not care when they see someone with an illness?
Sorry, I guess I kinda went into ‘interaction’ instead of ‘reaction’, haha…! They kinda go hand in hand, don’t they?