Anyone who wants school spirit with regards to sports teams will be frustrated here. We don't have the big weekend football games and most kids at this school couldn't care less. Also, anyone who is extremely intolerant of the bizarre and alternate ways of living. Half of MIT's campus is comprised of kids who could have been called "freaks" in high school. But that's the beauty of MIT. At a school this academically demanding, they don't worry about struggling to fit in. It's definitely opened by eyes.
People who aren't self-motivated or get discouraged easily - MIT's reputation is not without reason. People who are not independent will not be able to fully utilize the vast resources of MIT, and will quickly get left behind by those that are. People who do not enjoy math, science, and problem-solving, as that is the entire focus of MIT. Also, people who like to eat a lot may not want to come, because MIT doesn't have any meal plans and doesn't have a very good food system.
Someone who is not willing to work with other people to finish homework. These people would probably suffer from the work-load. A girl I knew from high school looks burned out all the time, and I know that she is not fond of working with other people on homework and projects.
Anyone who isn't willing to work hard. MIT can be a lot of fun, but you also have to be able to consider some types of learning fun, and to force yourself to work sometimes instead of having fun. It also won't help if you need a lot of sleep.
Liberal arts majors should not attend this school, as well as people who can't reason things out using logic. Since the graduate institute requirements (GIRs) are based around science and math.
Anyone that does not have an affinity for math, science, or engineering. Anyone that is not motivated to to work independently without constant urging from faculty or staff.
Someone who doesn't have a passion for math or science. Or who doesn't want to be required to take several science courses in addition to their degree.
Someone who is not truly passionate about their work.