Look up at the sky. Do you see the moon? Look at that moon and say, I want to go up there.
That's silly (except now it's not).
Look at that car, that big hunk of metal and say, I want to put that up in the sky and make it move around.
That's silly (until someone decided it wasn't).
Look at that overweight guy sweating buckets in the gym. He wants to compete in a bodybuilding contest.
That's silly (until he decides to win the contest).
Look at that single-mother of six working two full-time jobs to support her family. She wants to build her own business and be her own boss.
That's silly (until she decides it's not).
What we're capable of is not determined by how unrealistic or unlikely it seems. What we're capable of is determined by how willingly we embrace looking silly and risking failure.
Failure is not silly. Attempting the impossible is not silly. Having no idea what you're doing is not silly.
The only thing that's silly is dismissing something because it seems crazy and impossible. If something calls you to do the impossible, then go, be crazy.
Do something silly.