A "motivational" saying/acronym used by managers with little management ability. Similar to "There is no 'I' in 'team'," sans the overt conformity message.
The T.E.A.M. message can be found on numerous buttons, bulletin boards, et cetera, and is even the title of an $800 corporate training curriculum. The originator of this gem is, as far as I can tell, unknown.
As far as my personal experience with T.E.A.M., an ex-manager of mine once held an employee meeting and scribbled it, almost illegibly, on a manila folder and held it up in the air. This made little sense, as only one person worked in the store at any one time, but I just smiled and nodded.