I think I was around the age of 11, and got a brand new C64 with 1541 floppy. The manual of the included floppy disc with some programs described the program startup with 'load "name",8,1'
So I typed (exactly that) 'load "name",8,1' and got '?FILE NOT FOUND ERROR', did it again, same error.

After half an hour of reading the manual and trying it several times, I gave up and went to a friend with a C64. I told him the disc doesn't work, if he could help me out.

He put the floppy disc in and typed 'load "frogger",8,1' and seeing the command I realized what a tremendous idiot I was.
Surely it worked, he could play frogger.

Went home desperate and broken with my disc and from that day on I could operate that machine.
I soon started to play around with basic and a bit of assembler.