Poiple panic!
How can I avoid writing "purple prose", asks someone on Reddit, for what might be the tenth time today. Here's one of my many replies.
I would say this: “purple prose” isn't about showing, telling, or any specific wordcraft technique. "Purple" is when it's embarrassing to read because it's gone beyond what the creation of a work of art requires, over the edge into self-indulgence (oblivious or otherwise).
There's a long gradient between describing a thing so that the reader can imagine it and... talking to yourself while the reader overhears. People have various preferences, or tolerances, for points along that gradient. When you're writing, ya gotta read too— read the room.