Internships are the pledge terms of the real world. I can't stress the accuracy of this metaphor enough.
You want to join a large organization. It will increase your financial/social capital. But first you have to prove yourself. You have to voluntarily and without pay, place yourself at the beck and call of those who have already cemented themselves in the organization. Whatever they ask of you, you have to do. It doesn't matter if it's staying up all night to finish an Excel spreadsheet or to repair somebody's bong. You have no choice.
But you're not doing this alone. There are others who are undergoing this transition period with you. Sometimes they'll help you out. But it soon becomes apparent that part of this transition is separating the milk from the cream, if you will. Those who stand out in a good way will be put on a fast track to success and a position. Those who stand out in a bad way will be criticized and face consequences.
You will fetch lunch for hungover douchebags. You will bring people their coffee/beer when their body demands it. You will oddly be at the center of attention, while still being at the very bottom of the totem pole.
You will have to go to after-hours "fun activities." These activities will not be fun. You will be forced to spend time with people who you don't know that well and have lots of some terrible tasting drink like "Mad Dog" or "office coffee."
Being at the bottom sucks. You know pledge term is coming from a mile away, but an internship comes up and slaps you right in the face before you even know what's going on. And it's all because of what you were just doing.
When you enter pledge term, what were you before? You were a freshman. You were bottom of the heap. So transitioning to bottom of the heap is not really that difficult.
When you enter an internship your junior Summer, what were you before? You were president of your Greek house. You were the captain of your team. Or, at the very least, you had cemented yourself as the best Super Smash player on campus. Either way, you were top dog. And then, WHAM! You're somebody's bitch. If Newton were alive, he'd be scrambling to rewrite his laws of motion. The rate at which you fell from top to bottom completely disproves everything he said.
And the worst part is that, unlike a pledge term, membership is not a de facto guarantee when you finish your internship. You may never work there again and all your work will end up being worth only a line on a resume. Sorry about that whammy. And even if you do get hired, you don't get to enjoy the perks of employment (read: salary) for a full calendar year. What a tease. Man, internships suck.
THE LIGHT AT THE END OF THE TUNNEL for this issue should seem pretty obvious. I did my time fetching things and being at the bottom of the totem pole. Now somebody else is at the bottom of the totem pole. And hopefully, once I get a job, there will be interns. I'll be nice, for sure, but it always feels nice not to be at the bottom anymore.