Thanks for all your suggestions, syberspunk. It's really appreciated.
1. I only have University installed.
2. When a sim walks by, I greet them as quickly as it takes to cancel out working on a skill and getting outside. Pretty normal gameplay, right?
3. When they leave, under these circumstances, they do not have thought bubbles about their needs.
4. I don't invite sims over really late. In fact, I rarely ever iinvite sims over unless I want them to fall in love and get married to the sim I'm currently playing. Or if I want to get two teens to get the dancing scholarship. I keep relationships up using the phone.
5. You are correct in assuming that this on a residential lot.
6. I currently have 75 hacks in my Downloads folder, of which, 41 are by J.M. Pescado, 24 are by TwoJeffs, and there are 10 others. They are:
-- Jenflower's: "homeworksometimesfasterfun"
-- LizzLove's: "no-privacy"
-- LizzLove's: "no-jealousy-at-all"
-- Monique's: "No_Spoiled_Food"
-- Monique's: "Work_Bring_Friend_Dialog"
-- Inge Jones': "Crib Sleep thru Night"
-- Inge Jones': "Aspiration Flamingo (set to keep all sims on the lot in at least gold aspiration)"
-- Inge Jones': "No-empty toddler's potty"
-- Inge Jones': "No Kick Trash Can"
-- Inge Jones': "Always Stocked Fridge Patch"
Thanks again!