My house at school had an annual party, where people were set characters to dress up as. I tended to get a little more into it than others. because I enjoyed it so much I got set harder efforts.
Originally a friend and I started out talking about Bleach cosplays, and now we're discussing Attack on Titan and the like, since they're series that we enjoy, with great characterisation and awesome costume design.
I also have an unfortunate obsession with making things myself - it's unfortunate as I'm basically crap. I largely make things up as I go along.