Iâ€™ve only seen it like once before, so I thought it was a glitch/coincidence but, if a VERY mean sim is around a couple being romantic, theyâ€™ll get angry and irritated and do a â€śpsshhâ€ť gesture.
Finally figured out how to "undeepen" the basement in the House of Fallen Trees. (Don't use the GridAdjuster unless you are very familiar with how it works - I not only wiped out the basement and everything in it, plus getting stuck with two embedded and non-removable floor runners, but all the windows and doors had to be reset (and since it was an occupied lot, so did all the furniture and all the Sims!)
Recommended: make these adjustments before moving in any Sims!
First, find and remove all objects from the basement. You don't have to delete them; you can just move them upstairs or (preferably) outdoors while you work on the basement.
Next, delete all but the topmost stairs, and the fencing.
Then, paste a wallpaper with something at the bottom at the top of the inner basement wall, to use as a guide. Gradually raise and level the basement until it is level with the bottom of the wallpaper. (This is the tedious part, and you have to be careful not to mess up the ground outside.)
Then, go around the area between the basement walls and level it up as best you can (there will be a few troublesome spots, and you can't do anything about the outermost squares).
Then, check around the outside of the house just to make sure you haven't dug any holes.
Finally, replace all items in the basement as you please, redecorate as you choose, and don't forget to save.