We give up too early. 

When we were children, we were more disciplined. Think of all the times you fell off your bike.
Think of all the times you had to drown to learn to swim. 

Now, we see everything as an insuperable obstacle. 

The truth is that your dream is too weak, and you are too lazy to hit your head against a wall. 

So, if you want to do something, work for it and do not give up.