There is so much hypocrisy in these threads. Everyone saying you should only do YouTube "for fun" and that you shouldn't care about the numbers is fine and dandy, but it is invariably those same people who are the first to complain that their channels aren't growing, that no-one is watching their videos.....
YouTube isn't complicated, but if your goal is to actually grow a channel (and I guess, by definition, that's the case for 95% of people on these forums), then guess what? It's not all sunshine and rainbows. It is actually hard work. You don't have to do it for the money to be successful, but I'm a firm believer that you have to treat it like a business. The guy doing it "for fun" will find plenty of excuses not to upload a video (too tired, feeling sad, basketball on TV, party to go to), whereas the guy who treats it like a business has discipline, is goal-oriented and understands that sometimes you just have to suck it up and get on with it. That's not to say he's not having fun. These types of people are competitive and actually get enjoyment from overcoming challenges and reaching their goals.
A good analogy is people's jobs. Even the person with a "dream" job (let's say fighter pilot) isn't having fun 100% of the time and he certainly had to put in a lot of work to get the job. If he had just done the fun bit (the flying) and neglected the hard bit (ground school, exams, getting and staying fit), then he would never have got the job in the first place.