So, without getting into specific details (because of client confidentiality, of course), one of the many million things I have learned about nursing is how unlucky some people can be in terms of their health. Some people never seem to get a break - i've met people who have had various unfourtunate events or tons of comorbid dieseases. However, in many cases, despite the fact that many I've visited can't get out of bed, or are obviously in excruciating pain, they still manage to smile or make a joke.
It makes you feel silly when you feel like you've had a "bad" day. Especially when you are lucky enough to have a good family, or be in a good relationship, and have enough money to buy food, and are healthy.