I just want to give a quick example. I think a lot of people believe that when they're sick or in pain they have the excuse to drop their manners and be rude/mean. Often this means they are directly hurting the people who are caring for them.
I've been very sick this week and a few days ago I was in immense pain, throwing up, passing out. Not fun. At no point was I impatient, rude, or mean to my bf and he really noticed (his mom gets mean when she is in any poor physical state). He said that even when I'm at my worst I'm still amazing and everything he ever wanted.
I understand its a lot harder to remain kind and considerate when you're sick or in pain but why make the person who is trying to care for you have a worse time? It takes practice to learn to retain kindness no matter the situation but its important to practice now when we're young.
I've worked at a retirement center where the majority of older people are in constant pain. The older people who use pain as an excuse to be rude/mean were more likely to have been divorced and rarely if ever get visits from their children. They also generally received less care because no one wanted to be near them.
Next time you're sick, practice patience and remind yourself that whoever is taking care of you probably loves you a lot. The more that they love you, the more they will hurt from any mean remarks.