Something that's interesting about 4th year is the lack of continuity you have with your class. Everyone is on different schedules, away rotations, and often are not in contact with each other for months. Last year I heard of a student who hadn't been seen for over a year - she had been with her resident husband and children doing her rotations in another state during that time. The first time she'd been seen was when she found out where she matched...then she left again.
What's sad about this is the distance that seems evident between your friends and you. That relationship, developed during stressful times when you could discuss your hassles, irritations, and the like over dinner and movies, is being broken. Now there's really not a lot of people that I can talk to who will understand - even if they are here - because we're on different paths, or in different places, or have different mindsets.
Consider the person who is freaking out over their Surgery sub-I who tries to relate their frsutrations to another who's upset about their Peds rotation. At one time or another these two could have talked, given some pointers, and been more beneficial to each other. Now it's harder.
Sub-Internships have different feels depending on where they're done, what specialty you're in, and whether you truly want to be in that field or are just "being a tourist". I've had some phone calls and run-ins with friends recently and have noticed that I have a hard time relating to their pain, anxiousness, etc. because I've nothing to compare. The same goes for them, I'm sure. What the hell do they care if I feel like shit if I didn't get an IV, or fucked up a patient encounter, or something?
I'm really missing the interactions I had with people the last 3 years. I liked our movie and game nights, dinners, and bar jumping after a hard exam. I think that more and more I'm realizing that, while we'll always be friends and will hopefully keep in touch, we're headed on different paths, growing apart, and ultimately breaking away from the group to accomplish "our goals".
For someone like me who doesn't make friends easily, it's hard to come to grips with the fact that I'll have to go through this process all over again in residency.