People self-sacrifice frequently. This is bad for themselves. And it's bad for their friends, family, coworkers, etc, too. Do you want to interact with someone who is sacrificing? They'll get a little resentful and unhappy. Or at least they'll have to put lots of their effort into coping instead of being fun, productive, etc.
Self-sacrifice is tricky to avoid. It can result from stuff that looks harmless.
Consider group social situations. Someone says, "Guys, want to go watch the new Star Wars movie now?" Or they make another activity suggestion. That often results in self-sacrifice!
Most people look at an activity suggestion like: "Do I have a major objection? Would it be a disaster for me?" And if it's not awful, they agree to it. They don't want conflict, they don't want to be arguing all the time. So they try to avoid huge sacrifices, but not make a scene over anything small. But then they end up making small self-sacrifices all the time.
Trying to optimize things to match everyone's preferences in detail would be too hard for the problem-solving abilities that people in our culture have. It's especially hard in larger groups because there's more different preferences to coordinate. So people's preferences get trampled on. And they get used to that, it's just how life is for them.
Self-sacrifice and compromise are part of the status quo. People frequently don't even think about what they really want. They just check if they have a big enough objection that it'd be socially correct to bring it up. If they don't, they say they agree without considering if they are doing what they fully prefer or self-sacrificing.
People will focus on whether they have a reason to object to an activity that their friends will agree with, rather than focusing on whether any of their own preferences are getting sacrificed. The thought process is just trying to go along with things, not actually considering what one would most want, most prefer, really benefit a lot from, etc.
And frequently people agree to do something later which doesn't sound awful at the time they agree. But they weren't really that into it, they just didn't have a big objection. Later they get into some better activities. Then they cancel or sacrifice. So lots of people end up pretty flakey and irresponsible this way and cancel too often. They get into a dynamic of either sacrificing or cancelling a lot (which then annoys their friends and has downsides for them), rather than managing their life well.