So far it takes about 10 psi before I can really tell something is off, but at 80psi thats over 12%. Yea the back tires are easier to tell on a turn, that noodley feeling. I usually have to hit something with the front tire before I know if something is amiss there.
But if I'm going to tell the truth the flat looking tire is a bit of an ego thing. It would be like me riding in a shirt that is two sizes too small. With a tire that looks like it is about to go flat, I feel like I'm screaming I'm to big for this tire.
Now if someone ever said anything along those lines that wouldn't bother me near as much, but I couldn't promise I wouldn't make a remark back