A type to avoid going steady with is The Umfriend. The UF is someone who always introduces you as an acquaintance of nebulous status, as in, “This is my…um…friend.” Your companion may suddenly downgrade you from new girlfriend/boyfriend status to an umfriend when they unexpectedly bump into a recent ex who is either heartbroken-slash-psycho or someone your companion would like to get back together with (sorry, sucker).
To read about the other four types to avoid, go here.
Most people I know have been in this uncomfortable situation, myself included. There's nothing wrong with a "casual" relationship. But unfortunately, I see more casualties when confronted with the infamous 'umfriend' title. Although words like commitment and courtship make many cringe, there's a part of me that believes everyone is capable of it and deserves clarification when it comes to matters of the heart (or libido).
I guess it's all comes down to confidence and communication. All alliteration aside, I find that what was fun and casual soon becomes routine and expectations begin to surface. Unless you have a smarter solution, the second I feel like an insignificant other, I run.
Note: I'm not very fast... but I'm working on it.
I'm usually not one to solicit advice, but sometimes you'll read some thing that resonates...
Know your worth,
of Make Me Blush, Drive Me Wild