It's recently come to my attention that everyone is selfish. Every single living being is ultimately selfish to the core. Of course, this isn't a new concept. I've heard it said on countless occasions over my seventeen years, but the truth is I've only just noticed how damningly true it is.
Say you have a friend, and that friend is always nice to you and always helps you with your homework or your relationship problems or whatever shit you happen to have going on at the time. There are only so many reasons that this person is putting up with your crap for so long. Either
You annoy the fuck out of them and they just want you to leave them alone. They are only trying to fix your problems so you will stop whining about them and let them get some peace and quiet instead of waking them up at ass o' clock in the morning to complain about how your girlfriend left you for the infinitely more attractive cashier at Burger King.
Helping other people genuinely makes them feel good about themselves. Which is a truly admirable trait. But it's still selfish. They're helping you because they get a buzz out of it. In other words, you are best friends with an addict. Not that I've got a prejudice against addicts, because I don't. Just make sure you continue to bring this person every tiny little problem you have unless you want them to feel empty inside and turn to more hardcore drugs, like volunteering and charity work.
Somehow they ended up stuck with you as a friend and they don't want to seem like a bitch for screaming at you when you cry about insignificant things like your dead dog or your boyfriend having an affair when they would rather be curled up in bed with tumblr, ice-cream and the box sets of every BBC series ever made. This says more about their image of themselves than how much they care about you and your feelings. They want to be a nice person, therefore they can't lock themselves in their bedroom and pretend not to hear your screams of anguish outside the door.
Same thing applies to relationships, Even if your partner wants the best for you and loves you to the depths of your soul and does everything they can to make you happy, it's because you being happy makes them happy. The word 'selfless' is forever rendered superfluous, because no matter what you do, there's always something in it for you, even if it's just that lingering sense that you've done the right thing.