I joined a sorority kind of on a whim because my good friend recruited me. I later found out that she wasn't all that wild about it herself; she ended up transferring to another college in town and somehow being granted early alum status, as her new college didn't have a chapter of our sorority. I still tease her about reeling me in and abandoning me like that.
QuaerensIntelle, I definitely see where you are coming from. I had made some pretty good friends when I decided to quit, and I had a lot of doubts about leaving. I think I almost didn't quit (or "sever," as my sorority called it) because the stigma seemed so high. We had a good number of girls quit the year I eventually did and every time it happened everybody acted like they were so disappointed in them. I didn't want people talking about me that way. Eventually I realized that most of the people who would look down on me for quitting were people I didn't care about anyway, and the people who wouldn't make a big deal about it and wouldn't treat me differently were the people who I cared about and whose opinions mattered to me. That was one aspect of my decision-making progress, though I don't know whether it applies to your situation.
I had a good time for the year I was in the sorority; I don't regret doing it for the time that I did. It was an interesting experience, but it really does consist, as you pointed out, of paying to have someone boss you around. I've never considered myself a strong-willed or overly independent person, but some of the stuff they forced on us really aroused whatever defiance and rebelliousness I possess. My sense is that fraternities are much less dictatorial, but maybe that's just at my college.
Another issue I had with sorority life was all the forced intimacy and weird rituals. We'd have these ceremonies (pledging and initiation of course, but also various others throughout the year) in which we'd sing songs and recite pledges about how much we loved our sisters and how devoted we were to the sorority. Once I found myself singing one of these songs in the candlelit basement, holding hands with these two girls I really wasn't too fond of, and wondering why the hell I was supposed to feel about these people the way I feel about the two closest people to me in the world (my actual sisters). In that moment, and in many others, it all felt so fake to me that I could hardly stand it.
I am in no way trying to generalize my experience to other sororities, or even to other people in my own former sorority, most of whom are pretty cool people. I know lots of people who are extremely happy as Greeks, and there are probably plenty of people who think about quitting who shouldn't and might regret it if they did. There are also plenty of people who have reservations about quitting but really should get over them and bite the bullet and who would never look back if they did. For people in this latter group, I think the advice to seek a leadership role is misguided. That would be a good idea if you like the organization but want to feel more connected to it. For people who just aren't feeling it, I think it would only make things worse.