If you're the type of person who thinks you don't complain much, think again. Every little bit counts and when it comes to your motivation and mindset in this industry, you could cave your whole business in with negative thoughts and self doubt.
I know someone who is the most negative person I've ever personally met. He doesn't see himself that way at all, yet everything he discusses has some sort of silver lining stripped out of it.
It's hard to see yourself as someone who is negative. I get on that track sometimes but I have to stop and shine a light on myself and see what the purpose of it is.