Have you ever had a girl like "Summer"?

Have you ever had a girlfriend like the girl “Summer” in 500 Days of Summer? I find the character in the movie hard to figure out. I had a girlfriend back in the day that fascinated me and confused me all at the same time. We were good together; we were bad together. We had everything in common, and nothing in common. When I met her husband years later I couldn’t believe that she would even be interested in that type of guy.