Is the smell.
I love the smell of the laundry room, not just any detergent but the mix of many varied scents churning in the washers and toasting in the dryers. It is also the smell of independence - I was finally living on my own! Although now I much prefer having a washer and a dryer at home, I still couldn't help smiling and taking deep breaths every time I pass by the laundry room of any random building :)
And the song, of course.
Back in Oxford in my first year, I could never accurately gauge the time it took for the washer and dryer to be done with my clothes. And I knew that if I were to be slow in getting to my clothes, someone could take them out for me. Saying that I really don't like other people handling my clothes is an understatement; I'll probably wash them again! Thankfully that never happened. And it's because of a song. I would always go to the laundry room early and wait for my clothes to be ready, and I would sing "Part of Your World" in the tiny basement room while waiting. Just that one song in an entire year - I just liked it. Btw, the acoustics were really good in there!
Just now, I sang "Part of Your World" again. Not doing laundry, just random, at my desk. And it felt good :)