Persevering when you’re struggling through a problem sometimes requires knowing that it can be done. Otherwise, you’re likely to throw up your hands with an exasperated, “It can’t be done.”
After runner Roger Bannister broke the four-minute mile, other people quickly followed suit. Knowing it could be done allowed people to believe that they might actually be able to do it.
It’s why competitors rushed to market with tablets after Apple showed how.
Source: Seth Godin