Is happiness as an "adult" really so fleeting?
Yesterday morning was a good morning, and the afternoon started ok, but then it got retarded until I was pretty much coasting along at a basic level of disappointment and annoyance, which is all too familiar.
Why do people stab at happiness? How come people get so wrapped up in themselves and their insecurities that they can't let you be happy? And if you are happy, you must be picked at until you fall back down to their level and be unhappy like them?
I have a hard enough time being happy on my own - I don't need help bringing myself down.
Just an FYI.
Yesterday morning was a good morning, and the afternoon started ok, but then it got retarded until I was pretty much coasting along at a basic level of disappointment and annoyance, which is all too familiar.
Why do people stab at happiness? How come people get so wrapped up in themselves and their insecurities that they can't let you be happy? And if you are happy, you must be picked at until you fall back down to their level and be unhappy like them?
I have a hard enough time being happy on my own - I don't need help bringing myself down.
Just an FYI.

Meaning that for example, rich people don't seem to be more happy on average than poor people, they just find other things to be upset about.
As for your second point, I don't know why... but its been a universal constant long enough that we have a pithy saying for it - "Misery loves company."
At least I know, from observation, commentary and first-hand, that there is a point to my line of work, eh?
Find your contentment and fuck the squares. Sure there are highs and lows, but those are brief chemical rushes dependent on mood. Mood isn't happiness.
The key to success is being too dumb to know you can't do it.
The world is full of malcontents who are disappointed in the way their lives turned out - and this is because they did not even dare to TRY to fulfill their needs and desires. And they like to bring the rest of us down. People at my last job were like that. It was like an emotionally abusive relationship, where the other person is telling you you're not good enough or smart enough to be with anyone else.
And like Ace said so eloquently: Horseshit!
Anyone else, though the right thing is to be considerate and respectful of other's people's feelings, should not be allowed bearing in your own joy. If a random schmoe friend is bringing you down, at the risk of sounding cliche, they're not much of a friend are they. The unhappy realities of life only make the happy moments that much more precious. Are those precious moments worth "giving" to a random jerk who only wants to bring other people down? It's not selfish to step away and say, You know what, I just don't want to deal with you, I'm going to go forward and be happy, smurf you.
I'm not much into the "adult" phase of my life, but one thing I learned, to be happy you need to be happy in yourself, and not let other people bring you down. Because, yes, they will. If you are happy, there are people who unknowingly will attempt to bring it down, just so they are not alone in their misery. It's up to an individual whether or not they're gonna let them.