Why do owners complain about vet bills?

It seems like more and more people are complaining about the rising cost of vet bills. People seem shocked when they get a bill for hundreds of dollars. First off, it costs money to treat patients and second, it costs over $100,000 to get a degree in the field of veterinary medicine. I don't want to go on a rant but I'm just curious why people tend to have an issue with their vet bills.....the veterinarian has to make a living too. I don't hear about too many vets living a glamorous life....