This is minor, but god(dess)(s/es) how it annoys me...
Look at one of your credit cards. Notice how the digits of the card number are displayed in groups of four, something like "4111 1234 5678 9011".
Now, try entering the digits in just that way on some website where you want to buy something using that card. Odds are 50/50 that the site won't accept the input, that it will require you to type them in as the much less legible "4111123456789011".
There is absolutely no reason for this other than laziness or incompetence. Telling the program to remove spaces or dashes is trivial -- a decent program should be able to accept either format. (I've done it for my employer.)
Modern programming languages have a rich array of functions and methods for string manipulation. Learn to use 'em or go home and leave the programming to the grown-ups, kids.