Shoutout to the stuck thermostat bolt that ate my whole Saturday

I went out to the garage Saturday morning to do a quick radiator flush on my 65 Mustang and snapped the thermostat housing bolt clean off flush with the intake. Two hours later I was drilling it out with a left hand bit, and of course the bit walked and nicked the mating surface. My neighbor Dave came over, looked at it, and said "that's a helicoil job now, buddy," which is exactly what I did not want to hear at 4pm. $40 in bits, a $15 coil kit, and one very long day later it holds pressure fine, but I am done rushing jobs I have never done before. What is your worst broken bolt story, and did you drill it or just pull the whole manifold?