Yup. I found out fairly early on about the Insert/Overwrite key when I'd try to insert something and what I typed ate what was already there. Trial and error. Lots of error.
Kinda reminds me of Mrs. Slocum, who, for seventeen years in a row, walked down from the mountain to the little township clinic where she delivered her new—seventeenth—baby. When the nurse bundled up the baby and put it into her arms for her trek back up the mountain, she said, "Well, I guess we'll see you again next year, eh, Mrs. Slocum?"
Emphatically, Mrs. Slocum said, "Nope!"
"Oh?" said the nurse, "you're not going to have any more children?"
"Nope!" said Mrs. Slocum. "We finally figgered out what was doin' it!"