There are writers who, when they speak of their Muse, are basically personifying their subconscious mind. (e.g. “My Muse won’t give me the rest of the story, it just gives me the opening of a different story. Argh!”) If it works for them, great, and if it doesn’t work for them, it’s not my job to tell them what to do instead. I don’t know what I’m doing half the time myself. I do know that my subconscious is me, and that I’ve not derived any particular benefit from trying to personify it as an Other.
When I speak of a muse, I am usually talking of a male Film/TV character, or cluster of similar characters from the same actor, whom I like but feel like the source material doesn’t do justice to. These characters fascinate and irritate me, and that irritation leads to a desire to create new stories with characters *like* the muses. (Not exactly like, because I’m working in print, and usually there’s a decent amount of drift from the original to the character in my story). It’s more like a painter’s concept of what a muse is.
Last year, I took a long hard look at the muses I’d accumulated over a lifetime, and discovered that there were certain concepts or motif that kept recurring in them. Below, each row is an archetype/motif/concept, and each column is a muse, the column name-headings having been intentionally cut off. I found it very helpful in terms of understanding why I liked the characters I did, and why I wrote the things I did. I offer it as a potential help to people whose brains work similarly to mine, without disrespect to people whose brains work differently from me. (“different than mine” is bad grammar, and sounds ugly to boot. You have my permission to burn in effigy whichever teacher taught it to you.)