It's really not that it's necessarily an achievement, it's a subconscious bias to value the same product higher than if you don't invest time in building it.

It's a kind of "you're rewarded for your effort" idea.

I like the cake mix example where letting the consumer add eggs made house wives happier with the cake from https://www.psychologytoday.com/us/blog/the-shaping-us/20191...