3 ring binders
I was an Atari man. 6502 all the way. Player Vector Graphics (sprites for those of you a generation younger). Raw coding I/O cos you only had 32K to do everything. Using a standard routine as a loadable bit of script. Forgetting that you had hard coded the I/O channel to 0. (out of all of 6). Coming back 3 months later to use it again, choosing channel 1 and not knowing why it didn't work. Because I intended it to be flexible but forgot about the hard coded port. Documentation; who needs stinking documentation...
And of course, trying to find 3 ring binders for 'De Re Atari'. Still got mine. (De Re, I gave the binders to a friend who also needed them)
Fell in love with the 6809 - favourite op code of all time
BRN, LBRN Branch (short or long) never
SOURCE FORM: BRN dd; LBRN dddd
Which in the original documentation was described as "to keep symmetry with BRA (Branch always).
"JUMP - What now?"
"OK -- we'd better have a 'DON'T JUMP'"
I don't see that sort of humour in hardware often now.