You actually say I AM MR. ???? I've never seen anyone call themselves MR. Maybe I'm being americacentric? Is that a word? :)
It's actually not that uncommon for non-name uses your describing yourself as fitting a role...
Describing yourself as the "topic expert" at the company:
I am Mr Cisco.Or what you do:
I am Mr Fixit.Or a humorous title for something you do:
I am Mr SpamNinja.Or sarcastically:
I am Mr Perfect. (...and the rest of you all suck.)