Formatting a custom buff

I only know how to make it so the sim is happy to be on a residential lot, IF they have a custom trait. You could do it this way and then just add the trait via cheats so as not to take up precious trait slots. I use UI Cheats and More CAS Traits mods.

Anyway, if you wanna try it this way using Constructor5, make a new mod, then add element, Trait.
Fill out whatever details on the first menu option for the Trait.
Then add another element Buff, fill out Buff info.
Click on Trait in the left column, then go to Proximity Buffs in the menu for the Trait.
Create a Proximity Buff if you wanna just do a simple mod, or click Browse and select the buff you just made if you intend to make a bigger mod. If you make a small mode, and click create, click on the New Buff (Mod Reference) that appears. Fill out details.
Whether you create a new buff or add the buff element you made, the next steps are the same.
Add Condition. Click the cogs next to No Condition Selected.
Select Location Condition. Click the cogs next to Lot Type Nothing Selected, select Residential.
Now your buff will apply when the Sim with this trait is on a residential lot.
You can do the same and make a buff so they don't feel good away from residential lots too by changing the conditions.
Set Participant. Actor is the Sim who is DOING the action or has the buff or condition, and TargetSim is the OTHER Sim involved if any FYI.
I only just started learning this myself, so I'm sorry if I misinformed you at any point.

Hope this helped!

The buff SHOULD automatically go away as soon as the sim is no longer on a residential lot because it is a proximity buff, rather than some other kind of condition.