People want to be happy; that seems pretty clear. What makes people happy? Why, pleasure makes people happy. Bros fucking love pleasure. Pleasure is the only thing people want for its own sake, as an end; everything else people do is to attain some final pleasure. Pleasure is happiness. What the fuck else could happiness be? And what could be right, other than making people happy?
Can I prove it? No, that's not the sort of thing that's provable - we want pleasure, and that's it. If you can come up with something better, fucking be my guest. Therefore, the right action is the one that maximizes the ratio of pleasure-to-pain. If the people want happiness, let them have happiness.
Seriously, pleasure is fucking sweet. For some reason dudes keep insisting that there's more to life than pleasure. And to them I say, "Really? Like what?" When they start listing shit like literature and the arts and human excellence, I know they're not paying attention because all of those things are pleasurable. Why the fuck would anyone read Aristotle unless they got pleasure from it? There's literally no higher reason for doing any of the shit we do than for pleasure's sake. Just the other day I took some bitch to the opera. Bitches love opera. Now why was that a good thing to do? Because opera has some abstract, ineffable property such that those who can appreciate it are better than those who can't? If your bullshit alarm isn't going off, you should re-calibrate. The very people who object that we should appreciate the 'finer things in life' provide the best example of why utilitarianism elevates us above the animals. The more we appreciate them, the more pleasure we create.
I'm also not telling you to walk through life content with everything, never complaining, always satisfied. Fuck that. Socrates, one of the smartest bros in history, dedicated his entire life to understanding how little he knew. He wandered around trying to learn anything he could. He wanted just one. fucking. thing. he could know for sure to settle his dissatisfaction, and he was executed for his troubles. That sounds fucking crazy, right? After all, he could have stayed at home and touched himself all day, and no one would have killed him for it. Except that he knew he would be unhappy if he gave up on his search. Human nature pushes us to pursue higher pleasures, to improve ourselves constantly. The pursuit of maximum pleasure doesn't mean simple contentment, it means working our asses off to get there. Instant gratification is the easy way out, and it will cripple us eventually.
Besides, your pleasure isn't special. It's not more valuable than mine or anyone else's, and any selfish asshole who says he's a utilitarian is a liar. Think of how much happier everyone would be if they were educated - you think those in squalor or poverty are happy to be there? The greatest people in history are those who sacrificed their own happiness to the happiness of others. Say what you want about Jesus, but he let us nail him to a fucking tree because he thought it would make everyone happier. That's baller. That's what utilitarianism demands - the highest, most noble people are those who sacrifice their own happiness for the happiness of others. Only sacrifices that create more pleasure are virtuous sacrifices. If you sacrifice for any other reason, you're a fucking dumbass. It's not 'noble' to burn down your house for no reason. "But what a grand sacrifice I made!" So what? No one gained anything. You're not noble, you're an idiot. Enjoy being homeless, asshole.
If there's one bro who loves utilitarianism, it's God. Remember the Golden Rule? "Do unto others" and all that? Ask yourself - what do you want others to do to you, ultimately? If you picked "make me as happy as possible" then you're tonight's lucky fucking winner. No moral system more closely conforms to revealed truth than utilitarianism.
So, to sum up, there are a lot of dickheads out there claiming to be utilitarians telling everyone how to act, but that's true of any system. Fuck them. They're the problem, not the system itself; the system is fucking sweet, and the more you learn about it the more you'll see that. You have to decide between right and wrong somehow, anyway - ignoring pleasure or happiness or pain or suffering won't make them go away, and you can't come up with anything to replace them. We all know what makes us happy, what leads to pleasure; if you think it's too hard to decide, you just need practice. Trust me, you'll get it.