It’s quite a short list for me because I enjoy creating 23h55m connections so that I can spend a day in a city and see if it’s somewhere I’d like to go for longer. The list of cities I’ve spent less than 24 hours in is longer!
HGK (refuelling on my way to MEL)
TPA
LAS
LAX
CMH
DCA
MUC
like the OP, I should have been going to Washington DC recently but the trip was cancelled.
I’ve been to CLT about a dozen times but only been to Charlotte itself once.