I have heard it said that asking some to borrow their guitar is akin to asking to borrow their wife. :-}
I don't usually mind lending my guitars because the ones that I own are far from being considered top end. A couple though sound very good and often the borrower has more picking skill than myself. That allows me to appriciate how they sound in a masters hand.
A few years ago I was playing some songs at a local variety concert. I was using my old Eko J54 (Ranger) that is built like a real dreadnought.( battleship) Sitting in the front row were several folks from a group home for mentally challenged adults. They were real enthusiastic about the music and they were very appreciative. When I came off stage I was approached by a young lady from the group who wanted to try my guitar. The attendant with her was trying to discourage her but she was very insistant. I carefully passed it to her and let her try it. She strummed the open strings several times and passed it back. The audience gave her an applause and it made her evening. It also made mine but in truth I was glad that it was the J54 that I brought that night.