One might have heard the saying 'ignorance is bliss'. Ignorance can be happiness. If you have no knowledge of anything better than your current life, then why should you have any reason to be unhappy? But what if you do know of something better? Should you be unhappy with your current life, then? I think some people pretend to be happy by pretending to be ignorant.
I ran 5 kilometers in the pouring rain today. I know exactly how happy I am right now. I don't lie to myself. Despite what you may think, I am quite happy :D
If you are standing still then you are not really alive!!