How close you get to your professors depend on the class size, what class you are taking, and who you are. If you like to talk to professors during their office hours, or if the class size is small, or the class requires that you go to their office hours for homework, then you'll probably know the profs. I don't hesitate in asking my professors to go to my concert. My favorite class this semester is Music 1b, introduction to western music from Beethoven to Present. The professor lectures well, and the material is interesting. Students are quite enthusiastic in general, but sometimes there are people who fall asleep (we do study quite late into the night) occasionally. I feel that Harvard's academic requirements are quite reasonable. I do wish that I can take more electives. I never feel that Harvard teaches the materials that we need to learn to use in jobs, but Harvard teaches (indirectly, sometimes) the way how we can be successful at work.
There is definitely no shortage of large, apersonal lecture courses at Harvard. However, once you go past that and really start getting involved in your concentration (major), you'll find countless opportunities to get to meet incredible faculty, and work closely with them. Indeed, there are plenty of chances, be it office hours, faculty dinners, or simply chit-chatting with professors. The key is, nothing will be simply handed to you. If you sit by idly, these opportunities will pass you by. You've got to be assertive and make things happen. In terms of difficulty, Harvard courses vary wildly by department. The math, science, and engineering departments are very rigorous, and you definitely should not expect to walk away with a 4.0. However, if you choose to pursue one of the larger humanities concentrations (government or economics), you can breeze through six courses a semester with virtually no chance of getting less than an A.
Professors know your name if you make an effort to meet them (go to office hours), or if you take a seminar class. One favorite class was a seminar with Prof. Steven Levitsky. Least favorite class was a core, "First Nights" -- big waste of time. Class participation always happens in section, sometimes in lectures. Some students have intellectual conversations outside of class, but I'd say it's a minority. Most students are not too outwardly competitive, except for pre-meds. Most unique class - I haven't taken it, but I'd have to say it's the wine-tasting seminar. My major was Social Studies -- interdisciplinary social science, fantastic. Rarely spent time with profs after class. Academic requirements were fine, though they are changing (Core is being replaced by Gen Ed). Education is mostly geared toward learning for its own sake. Preprofessional training happens extracurricularly, and those programs are very good.
The quality of academics at Harvard is overall very good, but can vary depending on the class. Small classes like language courses or seminars are very intimate and you can develop a close relationship with your professor. In larger courses, though, there is definite alienation between students and the teaching staff. My least favorite class, because of this reason, was LifeSci 1a, which was huge, impersonal, and intimidating. I have loved nearly all of my other classes, especially my Spanish classes (Ca, Cb, 30, and 36), Lit-Art A-92 and ESPP10. They have all been very engaging and I have gotten to know the professors well. In terms of studying, Harvard students do it all the time--it seems to me that they feel guilty when they aren't studying. Competitiveness, however, hasn't been a problem. Students are hard on themselves and push themselves very hard, but not at the expense of other students.
So far, my coursework has been superb. Though some of the CORE classes are not that challenging and designed to fulfill non-major requirements (poets' math type thing), all of the classes I took, including a Core philosophy class, were interesting and well taught. The physics, math, and economics classes are quite difficult-- for freshman honors mechanics, I probably spent 10-15 hours a week on the problem sets. The Faculty are brilliant, but their pedagogical abilities vary significantly. There is little hand-holding, but with perseverance and some research, it is easy to find a great, great education. On the other hand, it is possible to just limp along, taking not-too-challenging courses; the education is largely what you make of it.
Professors are friendly for the most part and like to interact with students. Students are studying all the time, and it makes me feel pressured to study all the time even if it means not getting as much sleep as I would like. Harvard students do have intellectual conversations all the time, and are always up for talking about science, or politics, or the economy. I am a chemistry major. The chemistry department has a lot of focus on organic chemistry and that is what I like about it. Harvard's requirements are pretty flexible I think, which is great because then you can pick courses you are interested in. The education here at Harvard is more academic rather than pre-professional, which is what I like.
There's a lot of work to be done at Harvard. Just like any other university, actually, you can find classes to coast through or courses that will challenge you more than you ever thought possible! (The likelihood of those "coast" classes is probably lower here, of course...) Harvard students study, study, study, but at the same time it's pretty difficult to get a terrible grade if you do your work. The key to enjoying your courses (and challenging yourself) is, at least in my opinion, finding small classes -- which is almost always a possibility at the higher levels of any department. That being said, the huge intro-level courses are often well-taught, and help is always available if you're feeling lost.
I can sum up the academics at Harvard in the following phrases: - Some classes are ridiculously hard. Some classes are ridiculously easy. There is nothing in between. Therefore GPA says little about your intellect. - Some professors are totally awesome (who actually care), and the others are simply terrible (who don't care at all). Again, there is no one in between. The amount of knowledge you gain is correlated with how much the professor cares, not with the level of difficulty of the courses. - Good TFs are the key to good understanding of class materials - I can't emphasize this enough. If your TF is obviously unprepared/annoyed to teach the section, GET OUT. You'll suffer.
The biggest problem with academics at harvard is probably the overuse of teaching fellows. A lot of the time they don't really know the subject that well. Some professors know my name while the ones from the bigger classes definitely do not. My favorite class is probably Chinese, because the head prof is brilliant and extremely enthusiastic, also, the tf's for that class are very involved and clearly love teaching. I am also in a freshman seminar with two other students, so I've developed a good relationship with that professor. The academic requirements are really hard to get a handle on, especially if you're undecided.
Few professors do, Positive Psychology is my favorite class, MCB is my least favorite, students study every day for around 4 hours average, class participation is very common, Harvard students have some intellectual, students are either very competitive, or not at all, the most unique class has been positive psychology, my major is chemistry and it is a very tight knit community and i know everyone in the department because it is only 40 students large, i never spend time with professors outside of class, Harvard's academic requirements are easy, Harvard's education is geared towards learning for its own sake