Warning - anthropomorphizing dogs about to take place. If you don’t like it - don’t feel like you need to comment - I already know you are just that much better and smarter than I! 
Skip (the Great) is our min pin (miniature pinscher) and this year (like last year) developed a fatty deposit over his knee. He’s 9 and starting to get a grey beard, so I always fret a little over surgery. He got home at 2pm yesterday, since the vet doesn’t keep them overnite any more. But was so crabby and very likely sore (and groggy from the anesthetic) that he wasn’t really our Skip. Even the other two dogs didn’t think it was their brother - he was just too crabby and smelled funny.
Granted, he does get crabby on a regular basis, but last night didn’t want any loving at all. At bed time he just curled up under the comforter and growled if you so much as touched him. 
Poor little guy was probably hurting a lot!
This morning when I got up, he was perky, tail a-wagging and back to being a lot closer to his normal self. He wasn’t quite as spastic at breakfast, but that’s ok.
Its just really nice to have my little monkey back! 