It's about making sure you take a moment to appreciate the good things you experience. It's about making an effort to not assume malice when there's a plausible positive or neutral explanation for someones behaviour. It's about the fact that if you smile at people and say good morning, they'll return the favour more often than if you frown and don't. It's about making peace with the things you can't change. It's about not dismissing this stuff as happy-clappy bullshit, but about giving you energy to address the things that actually matter, rather than just going around being angry at the world.
Weather is a good example: If you find yourself constantly annoyed at the weather and it's possible for you to do so, why not go to somewhere with a climate that might better suit you?
I guess my point is, I agree, it's not worth it getting constantly worked up over stuff, but also one shouldn't ignore one's feelings towards certain things for a prolonged time.
The former can have quite an effect on the latter though. To take it to one extreme, if you're never happy you're not going to be satisfied with life. But more realistically if these habits often help you feel happy when otherwise you would've been less happy, then that's going to have a positive impact on how satisfied you are with life.