Most Helpful Girl
Because people without mental illness are naturally able to control their feelings, but others aren't. They don't get us in the same way we don't get them. Have you seen this? It's a comic strip showing what would happen if we treated physical illness like mental illness.
Most Helpful Guy
It is really hard to put yourself into someone else's shoes, especially with something as intangible as a mental problem. There's nothing to see except their behaviour - no broken bones, bleeding wounds, discoloured skin.
Plus, if it's in your head, that means you should just be able to switch it off, right? Or are you saying you're CRAZY and not in control of your own brain?
I've showed this to people to try and get them to understand: