Why are some sounds so delightful?

A fairly random selection of sounds that make me break out in a smile whatever mood I’m in. Pretty much anything produced with a sousaphone, though this is probably my favourite example:

The drum like counterpoint to the crescendo building in this acid techno track:

At a sound art event over the summer I heard the scrabbling noise a bee’s legs make as it climbs onto a flower. I can’t find a clip of this sadly but it was one of the most delightful things I’ve ever heard.

These are all very different sounds. I’m sure what provokes auditory delight varies immensely from person to person. There are also many other forms of enjoyment provoked by listening. What I’m describing are noises that involuntarily make me smile. It occurred to me last night, while listening to a sousaphone in fact, that the phenomenology is pretty consistent for me despite the variation in what provokes it. This is all the same kind of delight and I’m curious about what it is.