Compassion is difficult to keep from drying up as you grow older.
When you grow up as a lonely, misunderstood kid, you use compassion to seek that one spark of connection with others, because human beings are inextricably social animals. Little hyphae of concern and care take root in other people's souls, and while it doesn't net you any cool points or prom dates, it sure makes your life seem meaningful in the utter meaninglessness of youth. You still make some really great friends that way, and girls think you're a 'nice guy', which you, in your innocence, still think is a good thing. You come to know better eventually.
You grow older. You learn to stand on your own two feet. You fight back against the forces working against you, teeth bared and claws flashing. You understand where your problems ccome from and seek to deal with them in whatever way you do best. You feel like you're getting somewhere in your life. You have defied structure and embraced agency. You wake up one morning and realize that you somehow managed to convince people that you are cool. You are the person you've always wanted to be. Congratulations, you've grown the fuck up.
Other people become more transparent, more understandable, as you accumulate life experiences. You feel empowered, omniscient, as though you can peer into another person's soul and immediately discern the source and cause of whatever's bugging them at the moment. You are a sophomoric oracle of wisdom and platitudes. You can make the most meaningless thing sound profound. You awe your friends into believing you're better-adjusted and rational than they are, and cling to this pedestal with a white-knuckled grip.
But you overextend yourself, overestimate yourself. You think you can save everyone. You befriend people with the intention of turning their lives around, and are shocked when it blows up in your face. A cadre of maladjusted acquaintances crowd around you, calling you at odd hours, filling your ears with minute accounts of their problems, every conversation a confessional, every meeting a monologue. The classmate you tutored for a while now thinks that you and him are best friends and calls you every other day to hang out. It's really getting on your nerves. The barista at the coffee shop you always go to has been flirting with you so persistently that it's starting to get creepy and annoying. You have Facebook stalkers, and it's cramping your style and making you seriously consider closing your account and living your life completely in meatspace.
Is this what being popular's all about, you ask yourself. You see how these people could solve their problems; it's so obvious to you, because you've been in their shoes before and seem to have figured things out well enough on your own. You figure, if everyone just got over themselves for a while and realized that most of the drama in their lives is just invented and imagined for their own distraction, the world would be a better and calmer place.
It's hard to feel compassion at this point. They invented the term 'compassion fatigue' for situations like these. Contempt begins to creep in. You suffered in silence, so why can't all these losers do the same? You got over yourself, so why is it such a foreign concept for these people? You get the notion that they're just using you as an excuse to avoid dealing with their issues themselves.
At this point, you realize your cluelessness and realize that you're still in your early twenties, and no one has it figured out before thirty-five at least (and by then, it just might be too late). The answer to every question is 'mu' before thirty-five.