I always find it interestingly weird when I form seemingly random associations between different events. In my high school psychology class, we had the infamous "orange day," in which we did nothing for 50 minutes but listen to the Barenaked Ladies song "It's All Been Done" (I'm pretty sure that's the one... at the very least, it was the Barenaked Ladies) while eating a single orange. To this day, I think of oranges when I read the phrase "Barenaked Ladies," and vice versa, which was of course the point of the exercise.
But generally, my random associations were things that weren't prolonged, scarring experiences over the course of an hour, but rather something extremely random and short-lived. I still frequently think of Might and Magic (I believe it was Might and Magic IV, but I'm not sure) when I think of Saved by the Bell. I remember playing M&M while my mom was watching Saved by the Bell on the TV a couple dozen feet away from the computer.
Finally, sometimes I cannot for the life of me figure out why I associate certain things. Just now, while shaving my feet, I had the vivid image of my manager's manager saying something, but I don't know what it was. This wasn't like some "hmm, that reminds me, I should clip my toenails"; this was powerful, almost like a flashback of some sort, and I just intuitively knew that it was somehow related to shaving my feet. I don't know what to make of it. Maybe I subconsciously recalled him talking about shaving at some point. I... just don't know.