A little blast from the past, because it still applies:
To my health insurance company, for all the times you've screwed me, sans sweet talk, sans foreplay, sans lube and sans reacharound:
Just so you know, I'm going to enter your building armed with some fancy gun which shoots lots and lots and lots of bullets very fast. I am going to tell everyone but you to vacate the building, then I am going to make you walk through it, leaving nice little lumps of C4 everywhere. Then I am going to shoot the hell out of every computer, fax machine, printer, and even *gasp* the coffee and vending machines. After that, you and I will walk out of the building and detonate the C4.
As the police take me away, I will laugh maniacally at the thought of your insurance company dropping your coverage after they pay off your claim.