Sr vs Senior?

Why is "Senior Consultant" so often abbreviated "Sr. Consultant"? Is it just to save the 3 characters, or does the word typed out in full carry any negative connotations?

As English is not my first language, the subtleties of this distinction (if any) might escape me.

jm

At first I thought this message is a joke.

Giving you the benefit of the doubt, Sr is clearly just a shorter version of saying senior. No there is nothing negative about saying / writing the full word: senior.

Assuming this thread should now be deleted.

Don't get me started! The last time someone called me Mister Cool I nearly took their eye out...

Mr Cool

Thanks. No, my question was not intended as a joke. I just observed through LinkedIn that employees of certain consulting firms use the "Sr." form more consistently than "Senior".

By the way, according to http://en.wikipedia.org/wiki/Mister_(Mr.):

In fact, the form mister, especially when lowercased, can be considered a variant form of Mr that is often used humorously or to offend or an informal form used as a form of address to a man whose name is not known.