The biggest thing that pisses me off while driving - people who don't use their lights properly. These are the common misuses I've seen from bad to worst:
- People who use their nighttime lights during the day;
- People who use their high beams before it's dark enough for them to be effective;
- People who use their high beams in well illuminated areas that have plenty of street lights;
- People who use their high beams while they are driving slow enough that they aren't overdriving their low beams;
- People who use their fog lights when there is no fog / smoke, blizzard, etc, or even if there is but they are fast enough to overdrive these beams;
- People who don't signal for turns or lane changes;
- People who don't switch to low beams for approaching oncoming traffic; and
- People who don't switch to low beams when they close in behind me.
In general, using lights properly should be instinctive for any good driver. I see any of the above, and I treat it like they've written "I'm not a good driver" all over their vehicle. For the last three, I'm particularly cautious around them. If someone isn't signalling, there is a good chance that they also aren't properly checking their blind spots and mirrors, so I either make sure to get well ahead or well behind them. Also, people who don't switch their high beams off when they should can both distract and blind other drivers. At least with oncoming traffic, I can flash my own high beams at them to remind them to wake up, since usually they are just forgetting to switch them. For the ones behind me, there have been times that I wanted a rearward facing spotlight to flash at these guys, because I hate being blinded from bright lights in my mirrors. At least with the Jeep I'm both sitting up nice and high and have an autodimming rear view mirror, so it's not as bad. In my old Mini, that drove me nuts...