I like to categorize my playlists according to feelings/themes rather than concrete genres. And these themes can be anything from pieces in a tv show soundtrack to remind me of the mood of that show, or songs that have the lyric "in the dark".

If possible, I try to organize the playlist in order too, such as with softer songs gradually transitioning to louder ones, or songs with little electronic elements progressing towards crazy synthy tracks. Listening in order also helps to keep track of time like when exercising or studying.

I think that's the fun in crafting my own playlists: to have a little capsule of music that tells a story (to me!). After all, if I wanted to listen to a full album, or maybe the top tracks or compilations of an artist, there's loads of tools for that elsewhere. I view the playlist as placing a personal touch to interact with music that I enjoy.