The more you use them, the less you trust your own judgment behind the wheel
A lack of confidence in your skills can be incredibly stressful, especially when you're at the helm of an insanely powerful machine. Remember driver's ed? Constantly questioning yourself, checking your blind spot upwards of 15 times before you changed lanes, afraid you missed something? But a blind-spot monitor gives a driver external reassurance in his or her actions. Seeing the monitor's light, hearing its steady beep while parking, has a soothing effect. That's why it feels like a luxury to have them, and that's why they're marketed as, ta da, luxury options.
This need for reassurance can be addictive, and hey, I get it, feeling luxuriously calm and taken care of is easy to get used to. But what happens when you get into a car without those driving systems? Sudden anxiety forms over having to make decisions yourself: "Is someone in my blind spot? Am I drifting into the next lane? Is there enough room for me to park here?"