The risks of light bulb moments are many, but the rewards are great. You risk being killed stone dead, because you forgot which way the switch should be (off is good, but can be hard to predict on those two switch lights at the top of the stairs for example), an even greater risk is that the extra light will just show you that a particular part of the house, which you had thought was looking particularly snazzy lately actually has a huge amount of dirt temporarily hidden by the darkness, and then the worst risk of all is that you'll open the box of light bulb, yes light bulb, to find that it's got no two pins to hold it hanging up in the fixture or else it has - but your fixture is missing the holes to hold the pins.
my light bulb moments of this evening revealed one further risk - poorly matched bulbs. It's such a shame when you buy a bulb to put in a light that has three bulbs, and the other two are all fancy and pointed and the new one added in there looks like a complete tool (unfashionable or stupid person)
Don't say you haven't been warned.