Watching your garden grow
Planting a seed and watching it grow into a fruit tree, a flower, a shrub, etc. is very fulfilling. Of course watching something die that you have worked so hard to nurture isn't much fun whether you overwatered, planted in the wrong spot, lost it to a ravenous bunny or other cause.
Nevertheless, the next Spring you go at it again because you want to try something new or you want to split that grass and grow it elsewhere and see if it will thrive there, it is all a huge experiment but that's how a gardener grows and when they sit in their chair in the garden they are happy that the process starts anew with the promise of great things in the summer.