More seriously, ADHD, among others, is a working memory disorder. A way to cover this is to use "prosthetics" for it, such as a notepad that you always carry with you. If this affects you strongly, train your muscle memory to use it to note down what you were planning to do and to refer to it when you forgot.
In PC-speak, ADHDers have traded RAM for more CPU.
I've been taking notes religiously at work for years. So many notes. I have gone through dozens of note pads over the years. I recently switched from paper to Microsoft To Do. Works great for my purposes since I'm on my computer most of the time anyway. No more bulky note pads with disorganized chicken scratch.
How do you keep from getting overwhelmed by the list?