I've spent the majority of my life trying to make others happy. In essence, I was raised to believe that my desires and needs are less important than those of others. This philosophy served me pretty well throughout my childhood, keeping me on the agreeable side of teachers and parents. As a dating teen it betrayed me and landed me in a heap of trouble.
99% of the time, I really don't have a strong enough opinion to find myself at odds with my compadres. I'll eat anything, see any movie, shop anywhere, travel to any destination, listen to any radio station. And I'll even manage to enjoy myself while doing it. This is no sacrifice - it is simply not important enough to argue about this stuff.
There are times when I will sacrifice my feelings to honor another's. For example, I feel dreadful in a swimsuit. I hate the way I look and am pretty much convinced that everyone who lays eyes on me in that attire will run away, screaming something about their eyes. However, my girls are part fish, so several times each summer I don the cursed lycra and sit patiently poolside and pretend that I don't care how I look. In those moments they are more important than I, and it makes me happy to make them happy.
The problem with being so damn agreeable all of the time is that in those rare moments that you aren't, others react as if you have lost your ever-lovin' mind. Every once in a great while I have a need that is significant enough that I speak it out loud. When I do, it always seems to find itself at odds with someone else's need. And if it was important enough for me to speak it in the first place, it is important enough for me to stand up for it, defend it, insist that it be met.
Conflicts arise. Arguments ensue. Feelings get hurt. I end up apologizing, restoring the homeostasis, returning things to normal. Sadly, I'm not sure I've learned a darn thing from these experiences. But I remain hopeful.