It hasn't happened to me in a long time but I wrote an update statement and forgot to write the where clause. It was recoverable but a little piece of me still died. Are there any existing add-ins to prompt a user when they intended to run a statement missing a where clause?
I'm not aware of any add-ins that do that, but I've had that same feeling. I use the Custom Color option in SSMS to make all production servers have red banners, to force me to do an "Are you sure?" in my head before hitting F5.
The other thing to do is get used to BEGIN TRAN, UPDATE, look at row count, COMMIT. Just don't forget to commit or your phone will ring.
It's worked well so far (fingers crossed).