Funny HID lighting story and question

I recently got my first set of 600W HPS ballasts. I am a really new grower and I am not familiar with light ballasts quite yet. I have been testing my room all day with the lights on to ensure its safe to leave them on. A few minutes ago I decided to turn them off for a few minutes to check my power. I went to turn them back on and the bulbs didn't start. I TRIPPED BALLS for like 20 mins thinking that I broke my brand new ballasts. I tried like 3 times and nothing happened. I was like SO pissed that it broke so ez. Ten minutes later I try again, works like a charm. I am such a nub at this. Guessing it takes a while to cool down? Why did this happen anyone know?

HID bulbs need to cool down before you attempt to restart it. It is very hard on the unit to attempt to retart the lamp while hot. You should always give the lamp 1/2 an hour or so before restarting.

i was confused about that at first 2