- You run out of time (and quit).
- You run out of money (and quit).
- You get scared (and quit).
- You’re not serious about it (and quit).
- You lose interest or enthusiasm or settle for being mediocre (and quit).
- You focus on the short-term instead of the long (and quit when the short-term gets too hard).
- You pick the wrong thing at which to be the best in the world (because you don’t have the talent).
Seth Godin – The Dip.