YSK that if your turn signal is blinking unusually fast (like 3 or more times a second), it generally means you have a bulb out.
Why YSK: Your signals alert other drivers as to what you're doing; a signal bulb costs a few bucks and is usually a quick and easy repair to do yourself (consult YouTube); and any place that regulates motor vehicles probably requires you to have working turn signals. So knowing when and how to replace a burned out signal bulb can save you an interaction with law enforcement.
Adding: You can diagnose which bulb is out by turning on your hazard lights and checking all four corners of your car. It'll be the one not flashing.
This is also probably a good time to check your brake lights. Put something heavy on the pedal or have a friend hold it down and check that all three brake lights illuminate. Replacing a burned out brake light is also usually pretty cheap, quick, and easy.
I sometimes back into parking spaces that are in front of a glass storefront so I can see that my brake lights are working.
This is really smart. Considering tail light will get you pulled over, this can save you some pain. I never figured out a good way to check on my own. Thanks!
Another tip is asking literally any human.
Edit: the instrument board should also issue a warning.
What if Stevie Wonder is the only person around
Have him step on the pedal
But can I trust him not to steal my car?
Where is he going to go?
Spain.
Interacting with other humans? No thank you!
Also I've never ever seen an instrument panel that indicates when a bulb is out. Maybe that's a feature on new vehicles, but not one I've ever heard of.
I miss my ancient Volvo, it had that feature on all the lights.
A brick
One good way to make sure it isn't working
Reminds me of that jokes about the two hunters in the woods.
"911, what's your emergency?"
"Help, my friend got bit by a snake, and I think he's dead!"
"Stay calm, and check to make sure if he's actually dead."
BLAM
"Okay, he's definitely dead"
I think he meant "putting a brick on the brake in order to check yourself" but I guess throwing the brike on the lights also work.
Put on your emergency lights and walk around the vehicle?
Oh for brake lights, yeah, some weight probably works best, or backing near something and seeing if it lights up, don't even need a window