Even though you two might be rather different on the outside, there is still a sense of commonality between you, a sort of natural kinship and understanding that allows you to get along instantly, like best friends. The ways in which each of you deals with life are similar, and you rarely look at each other and wonder where your lover is coming from. Usually, you know exactly where they're coming from.
You identify with each other at a very basic level, and you relate to each other in a way that's really stimulating for both of you. You're similar, but not too much so; you're different, but not too different. There's just enough commonality between you to make the connection, but just enough difference to keep things interesting. Your energies blend together easily. When one of you wants to go out and have a great time, you spark the other up and get them in the mood for some fun. When one of you wants to stay home and cuddle on the couch, the other thinks this is a great idea. One of you brings the DVD and the other brings the popcorn! It's like that between you -- you naturally complement each other's personalities, and you find it really easy to get along from the start.