Shane O’Neill reminds us that reading is fundamental:
Glancing at the error message, the first things that stick out are the bits “{x,y}” so I change my regex to be anywhere from 1 to digits
"*\d{1,6}$"Why are you glancing, read the error message!
That doesn’t work, so I again quickly scan the error message and see the bit “following nothing”
“Quickly scan”?! No, actually read the error message!!
This wasn’t a great error message, but at least it does make sense after the fact and it’s a case where actually reading the error message does clarify things. The ones I really hate are “error 0x4849f8f8” types which aren’t even intended to make any sense to us.