Un-necessary use of car-horn, like stupid burglar alarms that go on forever. Cell-phones; that people dangle around like they were born with them. I suppose I would add talking on phone, in inappropriate places, too.
Noise levels in general have increased in society.
In London U.K in fifties. it was expected to be quiet through curfew hours. As a child I was told to do something quiet, no playing; on Good Friday's. Remembrance day, too. Nobody was the worst for it. You would hear the gentle clack of a push type lawn mower and the clack of garden shears. Through the summer. Now living here the sound of motor-bikes,snowmobiles and all-terrain vehicles. It's annoying to hear them on the trail.
Today, people fire up those machines; lawn-mowers, with tons of noise. Leaf blowers heard 2 blocks away and idiots gunning engines at the 4-way stop. One might reason? That it is the personality types with the largest demographic; that set the tone for society.