I like writing characters that are based loosely off of aspects of my own personality, just so I can relate and know where to direct them--except make them exaggerated, this way they can sort've come into their own.
I've written shy underdogs who become more bold and more powerful as the story goes on, and I've written crazy/demented characters who only become more corrupt.
But recently, I really like making personalities that seem very basic but actually have a lot of depth with many layers. For example, Saedie from my webcomic Between the Realms, comes off blunt, short-tempered, and crass. However, I've been exploring more of her softer side due to recent events in the series, so she's showing more vulnerability such as concern and compassion. There'll be more layers to her personality more, especially as she grows as a person. I like taking a basic 2D personality and turning it on it's head to make them seem more fleshed out and relate-able, and this actually makes them easier to write/draw
I still enjoy making villains or narcissists, it's just I haven't found my groove with these yet so they come off flawed and sometimes not as rounded as they need to be.