I just had a surprisingly emotional experience with the following song:
I was feeling a bit down, so I wanted to listen to some relaxing music. The thing about this song is that it just seems to exude a sense of comfort, like it's telling you that though things may be rough, everything's going to be okay. It must be the combination of low-key instruments: the piano, whatever the main instrument is, and the whistling. They combine to make a relaxing song that just makes me feel warm inside.
Now, I do believe this feeling is amplified by an external factor: nostalgia. For me, nostalgia is often not as obviously present as it seems it should be. I don't just hear music or whatever and think "hey I'm feeling nostalgia". Instead, I have to figure it out based on the fact that I just seem to like something more than I should. I think that's part of what's happening with this song: when I hear it, my mind always pictures two characters driving along Wario Colosseum celebrating, from back when I played Double Dash with my brother and we went to that course a lot because I thought it was cool. I think those memories from my childhood definitely contribute to the feelings I get. However, I do wonder if other people get those warm vibes from this song independent of any nostalgia for the game in question.
While I'm on the subject, I might as well mention another song that I seem to like more than I should for no apparent reason:
I just dig this song. It sounds so stylish to me, and I always picture the four characters endlessly running at the beginning of their journey to save the princess. In fact, the whole game of NSMBW feels real stylish and charming to me, especially this theme and the credits theme. I think this too is affected by nostalgia since I seem to like it more than it would warrant at face value.