A lot of people just don't care to do big things and accomplish big goals. They are fine where they are in life. I'm assuming you are reading this because you are someone who isn't fine with where they are in life.
I don't think you should ever be completely fine with everything in your life ever, until you are on your death bed. You should always want to achieve more and make your life better. This isn't to say you should never be happy with your life. Being happy with what you have is very important, but you should always have the desire to continuously grow throughout your life. But the key to achieving these things is not just to set big goals.
If I said, "I want to make a feature film," would that be a good motivator if I really didn't care all that much? No.
If I said, "I want to make a feature film because I want to tell a certain story," that's more of a motivator.
If I said, "I must make a feature film because I have to tell a certain story," that is the biggest motivator.
To motivate yourself, think of the "because" part of your goals and always turn "shoulds" into "musts." And think of the benefits the goal will give you by completing it. That will help motivate and excite you to do big things and achieve big goals.
It's all in the state of mind whether you can do something or not. remember that.