First of all, there are lots of different ways to do everything you want to do without joining a fraternity. A fraternity is a nice built-in social club, but there are other ways. If you are shy and introverted, being in a fraternity won’t make you magically not-shy and not-introverted, nor will it necessarily make you an instant magnet for girls and friends. I know a couple people who joined fraternities and sororities and still really didn’t feel like they made great friends in them (because they joined for the wrong reasons or they didn’t really fit or they didn’t make the effort to stay connected with the members outside of required events). I also have friends who are in Greek orgs who consider it one of the best decisions they ever made, but still aren’t necessarily friends with or even like everyone in their chapter. Simply put, there are a lot of different people and personalities that join Greek orgs, and not all of them click.
The short answer is that no, not everyone in fraternities is stuck-up, popular, and a jerk.
With that said, almost everyone I know in a Greek org did some investigation on the members of their chapter before joining. That’s the key. Most people’s stereotypes about fraternities come from the media, but you have to actually meet the members of the chapter that you would join before drawing those conclusions. Those are the guys you’ll be hanging out with for the next three years, largely, so that’s what you need to make your decision based on. Chapters of orgs can be really different at different campuses.
Also, resist the urge to stereotype the chapters - the “jock” chapter, the “geeky” chapter, the “popular” chapter - e.g. While different chapters might have different overall vibes or cultures, not every single person in that chapter is going to be the same. You might find yourself fitting in best with the chapter stereotyped as “jocks,” for example, because even though they are stereotyped that way from the outside because they all play sports maybe they’re just all really good guys with varied interests and personalities.
It’s also a common misconception that what fraternities are really about is drinking and partying. One, that’s what college movies typically portray them doing, and two, those are usually the public events that they do. But fraternities do a lot more than that. For one, fraternities tend to have higher average GPAs than the general population of the school. For two, they tend to spend a lot of time raising money for charity. I have friends in fraternities, and when I think about them - yes, they love to have a good time, but they’re also highly educated and very involved in their communities. The first three that came to mind are now PhD, MD, MD. Even in college, they posted way more pictures of their community events and scholarship galas than they did of parties they sponsored. (Usually when they threw a party…it was to make money for something else they wanted to do!)
Also, as a last note…you might not want to call them “frats.” That tends to annoy them, especially in people who are not yet members but might want to be.