Literally had several doctors throughout growing up tell my dad my brain is fucked and doesn't work like he wants it to cause heckin ADHD or whatever.
Everytime my dad was sure I was full of shit and, "just not trying hard enough to remember things or do things, etc"
Some people just aren't maleable enough to adapt their world view when presented with information that contradicts their preconceived assumptions and biases.
That "just not trying hard enough" hits so much harder because you are trying your heart out and dealing with the frustration of not seeing results AND having someone belittle your efforts.
For me if it is really important to remember, I write it on my hand because I won't lose it or not look at a note pad for a week. If I do lose it, I have bigger problems to deal with than what was written on my hand.
Also need to remember to write it on my hand in the first place.