I have just moved from a big 5 bedroom detached house post separation, into a mid terrace 3 bed.
I love it. Things I love:
Not having to clean the damn huge house. I am constantly amazed how little time it takes to clean my terrace and therefore how much time I get back.
Maintenance - the detached house was a constant round of maintenance, because obviously it had 4 external walls and also 5 different roof levels - including 3 flat rooves (nightmare!) It was like painting the Forth bridge - once you got to the end re. decoration and maintenance you had to go back to the beginning and start all over again.
Bills - my terrace is sooo cheap to heat as it only has 2 external walls front and back, no huge loft space sucking heat out, and you kind of get insulated by the houses next to you.
Security - XP used to work away quite a bit and it would just be me and DD in this rather huge house with plenty of access points for potential burglars - I actually got bolts on my bedroom door for the nights when he was away. And one night when someone did try and kick our front door in and XP was home, he didn't hear because he was at the back of the house at the time leaving me to deal with it!!
I am fortunate to have quiet neighbours but yes of course I hear them at times, but I quite like it and find the sound of other humans quite reassuring in lockdown!
I had a huge garden - again, a nightmare to maintain without paid help. I had three huge trees and come November I had to do the back breaking work of clearing up two trillion leaves only to find another two trillion on the lawn the next day! I do NOT miss that.
Do I miss the space - a little I guess, but it only encouraged XP to hoard stuff because we had so much space to store crap. The amount of crap we had when we eventually started sorting out to pack up was embarrassing actually. My terrace teaches me to be selective and only keep stuff I really love or is really useful. Large houses cause you to hoard a bit.
So all in all I can say - downsizing from detached to terrace living suits me.