I agree that the original poster needs to calm down, but I get the impression you should calm down, too. I've been avoiding getting involved in the generational battle that seems to have been sparked here over the past week, since I didn't want to add fuel to the fire. But this comment struck an unhappy chord with me; it just seems a bit too indignant.
I think the problem I have is that the assumption it is based on is wrong. I can only speak as a representative of the millenials, but the motivational power you have identified is incorrect. I am not working off of the assumption that everything I do ought to be fun. Given the discussion I've observed here so far, this seems like a gross exaggeration of what has been said.
The primary motivation for me is to be productive and build things people find useful. It seems that this is the same primary motivation of the original poster, too. If things are uninteresting, if they are laborious, if they are maddeningly menial, but they need to get done, then I have no problem getting them done. If, above all of that, they are pointless or otherwise seem like a counter-productive waste of time, then I will get demotivated, and my productivity will slow. As a result of my productivity slowing down, I will become unhappy and start asking questions similar to that of the original poster. I like getting things done, and when I feel like I’m running in place, it begins to make me ask why I’m not just standing still. Your position on this seems to be that I should shut the hell up and just keep running, if I know what is good for me. Can you be so kind as to explain why it is good for me, or those who have ordered me to keep running?
Obviously, if fed with an endless stream of menial work, my motivation will suffer as well, but I suspect that is not where the original poster is at right now. If it was, would you still be yelling at him to suck it up and get back to work? At what point do you decide that there really _is_ a field somewhere else with greener grass? I hope you are not so cynical as to say the grass everywhere is indistinguishably parched.