I've had my share of adult roommate experiences. I've been fortunate to have had some great roommates--roommates that share my values, my taste in food and decorating, and love of cheesy movies (except dancing/gymnastics movies--those are not allowed in my home.). I've learned a lot about sharing my space and life with someone else. Whether you are rooming with a best friend from preschool or someone you are just getting to know, I think there are several things that make a roommate relationship successful:
1) Eat together. My last two roommates and I committed to eating together whenever we could, at least once a week. The current Roommate and I have taken to cooking together, too. I've really enjoyed spending the time in the kitchen and at the table. It's much easier to talk about things around the house when you are relaxed and sharing a meal. Last night, the Roommate and I made sweet potato fries and meatloaf (shut it, it was delicious!). We had a great time making the food and talking and cleaning up while we waited for everything to finish up in the oven. And the kitchen was sparkling when we finished.
2) Verbalize your specific needs. I need to have a quiet place that is free from disturbances. I bought a reading chair for my room. I tell my roommates, when I'm in the chair, I don't want to talk. It's not code for I hate you, leave me alone. It's code for I'm thinking, I'll talk to you when my brain has recovered.
3) Dishwashers. In college, our three-person, no dishwasher combo bred ill feelings quickly and often. With a dishwasher, the load what you see, unload what you see policy works well.
4) Have a social life that is uniquely yours.
5) Share your life with your roommate. It is important that your friends know, respect, and care for your roommate (and vice versa).