While filling out any computerized form, the most annoying thing is to see a validation error like “Don’t enter spaces and dashes” after entering a phone number. This is the indication that the form was created by rookie developers, tested by careless QA engineers, and the project was managed by an incompetent manager.
Just now I was adding a contact to my telephone directory on my iPhone. Guess what, there’s no way to enter anything but digits, and the the number is “magically” formatted into the something like (222) 555-5555.
You say it’s a little thing that’s easy to implement? Wrong. Such huge little things make iPhone to stand out. Just because they cared to implement them.
What about you, my fellow software developer? Do you annoy the users with the messages asking to stick to a certain data input format? Then you suck.