... people that care enough to let me know when I have a light out on my car.
As a pilot, we are taught to do a preflight check of the vehicle. Checking anti collision, position and landing lights are a big part of the preflight check. Now most flights take place in conditions where these checks are 99% meaningless. The lights are simply not bright enough to be effective during day VFR conditions. Making them bright enough to be effective would require spotlights and simply not practically effective.
Drivers are not drilled to the same extent. We had a rainstorm today and had to meet someone at the airport. I pulled up behind a van and noticed a difference between the L & R headlight reflections. I wrote it off as a bad angle on the R light.
Fast forward a couple hours. Friend surprised me with a call 2 mins after we'd said good bye. Friend tells me the right headlight is dead. Now the weather today sucks and it could be a simple short. But it could also be a blown bulb. I am 100% thankful for the call. I would rather know there is a light out than learn about it from a pair of flashing lights in the rear view.
In the same vein, anytime I notice a similar problem, I will offer up the same alert in a friendly way. ("Wouldn't want to give officer friendly any excuse....")
Anytime you notice a friend with a brake or position light out, let them know. They may not be especially thankful, but they should be!