Okay, this might be a bit controversial, but this song is in my opinion really comfy and pleasant. (Also, we're not limited to Pokemon songs, right?)
https://www.youtube.com/watch?v=i6cwPzCkktUWhenever I listen to it I get that "Summertime adventure" feeling. Heck, a lot of Youngr's work does that. It might seem like generic pop, but I dunno. It seems much different in my opinion. It's just so upbeat and cheery, I can just imagine a collage of photos from vacation and two great friends looking at them during hard times and reminiscing about that better time.