Things that are commonly known and yet you forget about them a lot?

I have one.. When talking about money, I always forget if the dollar symbol ($) goes before or after the amount.. Because of this, I'll normally type up dollar amounts like "300 dollars" or "$300$"..

How to use words... slang or some such nonsense

When writing a story or posting something I seem to forget how to spell simple words like describe or dictionary.

Punctuation. When I was younger (still in school) I was really pretty good at it. It (English) was actually my best subject in school. On more than one occasion, my teachers had to remind me that they weren't working on that chapter and that I needed to turn the page to the proper one. I had to tell her I had already read that one...and the one after that. But over the course of the years, as well as abusing my mind and my body, I've kind of forgotten a few things. I'm still able to get my point across though, for the most part.

Basic math. I can add, subtract and mutiply but division and algebra are non-exsitatint.

sumteims i forget how to write .

.-.

I can't think of any at the moment.

I have trouble with this as well, being that I'm disabled in it. My strongest field is in writing, and I have other interests that help my imagination.. but for the most part math has always been gibberish to me

Not wearing pants is not proper etiquette.

Breathing. It's harder than you think.