oh, one thing I used to do (and caught my self doing a couple months ago) was making a text en/decoder, you would input a string, it would cycle through that string, and on every line was a "If Str2='A':'Z'->Str3", I knew about instring() and sub(), but never thought to together   I think that's how I got so good at getting to the strings through menus

In many cases, I often accidentally used two : chars between lines of code

I also put my entire programs in one single line of code. In some ways it is good, though, because it saves a lot of time with 2:Goto and when manually scrolling through the code. Otherwise it is risky, because if you press CLEAR you lose everything and the code is hard to read.

Another thing I did a few times: I decided to switch to lowercase letters in some of my BASIC RPGs. BAD idea. I did not realize about lowercase letters being two byte tokens. I eventually ran out of RAM

I am glad Axe Parser at least remove those from compiled code (altough sadly, if you lose your source, all you can retrieve afterward is the ASM disassembly of your Axe program, free of all comments)

lol, I did that too, for the guessing game I think it was, the one that was in the manual, I used MOS to give me lowercase letters, and wrote out each command letter by letter.  I learned later the meaning of that random catalog button on the 0 key.

I also used to get really screwed by the way that MOS turned on fast keys, and the lowercase letters one (though not as much)  I had no idea that those were even in MOS, I just assumed my calculator was spazzing out, when I tried to insert a line, I'd delete 5 letters, when I tried to move one letter to the right, I'd be halfway down the page.  The only way I knew to fix it was ram clear, then not run MOS (I figured out that MOS was doing it after a while, so it became less my favorite shell).  Then I went to DetachedSolutions, and saw that MOS had those options

The first platformer I ever made was exactly 9001 bytes ... and I wasn't even trying. In fact, I'd never even heard of the meme.

Kinda like xLIB xLIB Revolution

You needed to ungroup a level everytime (and they were HUGE!)

In the original version of Portal the external level editor always saved to the same custom List, and was always loaded from the same custom List.  So you could only have one custom level on your calculator at the same time unless you were tricky

Yup, but I've still used it to make levels of my own.