I just don't see how being "impressed" with yourself is anything other than ego.
Well, I was reading, "impress yourself" as, "feel your writing is of quality." I know it's harder to be objective about my own writing, but a large part of my journey as a writer has been becoming a better critic. My standards have risen in direct proportion to my skill as a writer, and I'm much more capable than I used to be of seeing flaws in my own work.
The main reason I want to "impress myself" isn't about ego* -- it's about making sure the work is some level of quality in my own judgment (and who else's judgment do I have?) before I share it. Sure, nothing's stopping me if I want to throw my work out there when I think it's crap, and maybe it would even get read, but why on earth would I want to?
(* I'll take it as a side benefit if I actually MAKE it to that point
, but being hard to impress means it's much more difficult to be egotistical about my work!)