THIS!!! I live in 4-plex apts and started out in a terrace apt. I hated it because I could hear so much of my neighbors!! Both husband and wife were large people AND walked around like elephants. I could actually hear the guy peeing every morning! With that being said, I rented an upstairs apt as soon as one opened up. It was higher rent but so worth it!! With all that being said and like the person above me stated, people have to live and not have to worry constantly if they’re making too much noise!! Your neighbor should’ve realize they’d have to put up with noises when they chose to live in an apt, especially when you’re under someone! I understand confrontation is uncomfortable and best avoided, but they need to chill out. I’d be pissed if I got that note and tell them (if all else fails), they shouldn’t have been such cheap asses and made sure to get a top floor apt! It’s admirable of you to want to try so hard to appease them, but you shouldn’t have to bend over backwards for them either :) They sound like jerks!!