Why am I a Mike?

It’s inevitable that when I go to a restaurant and they ask for a name that when I say, “Michael”, they always put down, “Mike”. If I go to a deli, I am always a “Mike”. Calling up a shop, I am a “Mike”. Phone solicitors will call me a “Mike”. People I meet and introduce myself to as “Michael” will then call me, “Mike” within a matter of minutes. Why is this?
There is the fact that people in the US really like to shorten things. I mean, why say “United States of America” when “USA” will suffice? But, that is a choice made by the individual and they can call the country by whatever name they want. When it comes to a person, it would seem that you call them what they request unless they give you an alternative.
But this is the problem with short nicknames in that they’re all over the map. For instance, how did, “Jack” become a nickname for, “John”? That’s not shorter. Yes, “Mike” is shorter than, “Michael” but not by much when you think about it.
This isn’t getting any closer to answering the question though. Why do people rename me without asking me? And it really is just me. “Josephs” don’t become, “Joes” and “Margarets” don’t become “Marges” automatically. More to the point, “Barry” would never become, “Bar” or, “Adam”, “Ad”.
Ultimately it all revolves around the fact that I don’t want to be a “Mike”. “Mikes” like sports and beer and driving lowered Hondas as well as raised Ford trucks. I like being, “Michael”. It’s the name I was born with and even though it’s pretty banal as far as originality goes, it’s still my name.
I don’t expect anyone to change here, but it makes me look forward to Europe even more when I go there because no one screws with anyone’s name there. I don’t know if it’s because people have more respect for each other, or there are more cultures and thus unknown nicknames, or just that it’s an American thing. Since, as Butch Coolidge so eloquently put it in Pulp Fiction, “I’m American, honey. Our names don’t mean shit.”
Why am I a Mike?