"Many patients say after surgery it is the small things that are the most significant to them," says Prof Simon Kay OBE, a consultant plastic surgeon.
"Being able to brush their daughter's hair, take money out of a purse or turn on the tap and fill a glass of water, and to feel complete again."
Or, in the case of former West Yorkshire pub landlord Mark Cahill, save his wife's life after she suffered a heart attack.
Leeds, the home of the UK Hand Transplant Unit, is the UK's only provider of this type of complex surgery. It is also now considered one of the leading hand transplant services in the world. It's an area of medicine that would have seemed implausible just a few decades ago.
Mr Cahill is the poster boy for this unit. In 2012, his right hand had become so badly infected following years of gout that it required amputating.
He addresses Prof Kay as "Prof", revealing a familiarity forged through years of interaction. When the consultant takes hold of his patient's hand and inspects his work, the connection and pride is clear for all to see.
Some patients who have walked these corridors over the past decade lost their hands or limbs due to accidents. Others lost theirs to medical conditions such as sepsis or scleroderma.
"My mother had seen Professor Kay on the television saying he was going to do hand transplants," recalls Mr Cahill, of Greetland near Halifax. "I managed to get to see him, and he said I was an ideal candidate. I talked it over with my family and thought I may as well go for it, it's got to be better than what I've got, which it turns out it has been."