I've just started dogfooding the Unit Testing in VSTS and it has totally blown me away.
In fairness, I suspect if I'd been using NUnit with its VS plug-in or TestDriven.Net , I might have had at least a portion of the same reaction - but I haven't, so I didn't.
Up until now, our unit test framework has been strictly a command-line affair, with editing config files necessary to run tests in the debugger, and trawling through a huge results file the only way to find your test output. Oh, and to run just one TestMethod you had to go comment out the other fixtures and recompile (in a different cmd window) etc. In short, it was all a pretty sucky experience.
I'd read all of the words that told me that "green lights" made a huge difference to the psychology of writing unit tests and not really believed it deeply, but one day at this and I'm hooked.
The convenience of being able to compile and run tests on the fly and then to pick the particular tests to run (or debug) trivially is fantastic. But I'm just about self-aware enough to realize that it’s the blinken-flashen green lights that are doing it for me. I'm in a hurry to get my test written so I can see that column of ticks light up green just one more time.
Suddenly its just not a chore and I can see that test-driven is something that wouldn’t drive me insane, but rather make me happy.
As always, it comes down to the quality of the tools, the quality of the experience and reminds me just how pleasure-motivated we all are even in our most business-oriented tasks.