e, in the Boston area, the term New York Yankees is somewhat offensive, but only because of that team's rivalry with the Boston Red Sox, and the term yankee by itself connotes hard-headed practicality and common sense.
There is, or was, a TV show called The New Yankee Workshop.
There was even a Broadway show called Damn Yankees! Way back in the 1950s!
Yankee is about as offensive to Americans as Limey is to Brits, I would say. It all depends on context and tone of voice. Someone could say
You yankee bastard!
and it could be construed as meaning anything from vituperation to casual dismissal to downright admiration. It would depend on who was saying it and how it was being said. The same thing could be said about the term American, in fact. Said with a smile, it's friendly; with a look of hatred showing from behind the sights of an AK-47, not so much.
A little more evidence that Americans don't think the term is derogatory:
(Also known under the title A Connecticut Yankee in King Arthur's Court.)
I could go on. But the people who are downvoting this answer wouldn't read that far anyway.
P.P.S. (for @J.R.):
The term 'yankee' is on the derogatory spectrum, but is weak to the point of being only nominally so. The word can be used in polite conversation, it is not vulgar or shocking in and off itself. No one would take offense at being called a Yankee (great offense may be intended, but the word itself carries no stigma beyond the implications of the de facto meaning of the word).
There are two primary definitions of 'yankee'
- someone from the US (to someone outside the US)
- someone from the north of the US (above the Mason-Dixon line, to someone from the south)
(there are more refined and humorous definitions say by E.B. White; the above two are the most prominent and relevant).
For someone who is not a Yankee to call someone else a Yankee (and who actually is a Yankee), the caller may mean it derogatorily, but the callee won't take the word itself as disrespectful. That is, the same emotive feeling could be reproduced by using a more formal term like American or Northener, there is no shock in using or hearing the word or being the callee.
This could be compared with 'white trash', definitionally 'poor white Southener (in the US)', which is fairly impolite and would be taken as hurtful by the callee.
From the UK, I would not call someone a Yankee ( or Yank ) unless they took the appelation themselves, because I know that some Americans do find the term offensive. It is rarely used here in anything other than a derogatory fashion, but is quite mild in intention ( maybe not in receipt! ).
I woudl say that using it within the US - as a Southerner to a Northerner - it may be taken as rather more offensive. I would suggest not using it, because someone may be particularly offended by it, while others may not care.
Yankee is one of those terms that were originally used in a derogatory manner (see the song Yankee Doodle) but has since been reclaimed with pride. For reference see Chicago's nickname "The Windy City". It was originally used by New Yorkers to criticize the native Chicagoan pride, calling Chicago a town of windbags (which still continues to this day). Also see the Second City as in Chicago is a second class city compared to New York.
Yankee was used by Brits as a slur to Americans during and after the Revolutionary War. As someone else pointed out southerners use the term to describe northern Americans. Few Americans refer to themselves as Yankees today, but during the Revolution, many Americans used the name with pride to describe themselves, thus taking the sting out of the Brits' usage of the word. Ironically, it goes hand in hand with the British view of Americans as a bunch of slack-jawed yokels. "Look at them, they don't even know when we're insultin' them."
I lived in England from 1969-71, and attended Grammar School in Cheltenham, GLOS. As a US citizen and one of only two such in the school (the other was a teacher there) I was referred to and addressed as "Yank" occasionally by my peers (although never as "Y