Customer Service? Please?

Okay, I know I haven't worked forever, and I am not some kind of Uber-experienced manager or anything, but after working for Bashas, Renzi, NAU, Patriot, and UT&T, I like to think I understand that customer service is the most important part of any business. It's also not that difficult to do if you set your attitude right from the get-go that you, as an employee, are there to provide a service for a customer. Why, then, do I still have to deal with rude, uncooperative, and frustrating people when I walk into some businesses? Today my brother was supposed to take our dog down to the vet to get an updated rabies shot, but the women at the desk decided it would be funny to allow him to sit in the store for 45 minutes before telling him that they weren't doing vaccinations until two hours later. That was also when they told him that he couldn't get the vaccination - he's not 18. 45 minutes! So he came back home, and I had to take the dog back to the vet, wait AGAIN to see the vet after having words with the staff, and postpone a job interview in the meantime. Seriously, how hard is it to be up-front with customers instead of having them wait for hours? How hard is it to be nice while you work? All the more reason I should be looking for a job in leadership/professional development. I am good at it.