The only expression that I really cannot stand is "innit". Drives. me. crazy.
How could I have forgotten that one?! Hate it!
My most-hated corporatespeak term is "incentivize". 
People actually say that? With a straight face? Oh, I would find it very difficult indeed to not roll my eyes in response.
I keep waiting for one of my favorites to show up on someone's list: duck! As in "ey up, mi duck," not as in "there's a cannonball coming this way, you should duck." I don't say it myself, but I was terribly excited the first time someone here called me duck. Is it just a Derbyshire thing? Google seems to say East Midlands, though I've never heard it said in Notts/Leicester/etc. I still find it strangely endearing, even though I hear it almost daily from all postmen and most cashiers. I guess the charm hasn't worn off yet.