Oh, I agree. I don't think we should be miserable. We'd be a lot less miserable with less stuff and more friends. Less internet (probably), more music and hobbies. Yet here we are :)

Many of us aren't miserable, love our stuff, and love our music, friends, and hobbies! And I suspect many more would be in the same camp if they weren't being told so often that "everybody's miserable."

When people hear "the world sucks" enough times, they start think, "the world does suck", and easily enough that leads to "my life sucks". Hearing that the world is great can help have the opposite effect. But it's often derided as foolish or even insensitive not to dwell on the negative.