I have found that the older I get, the more I cannot stand to hear chewing or gums snapping, etc. Heavy breathing is bad, too. And, yes, public whistling/humming is a bit irritating.
Probably. It's stuff I've noticed more the older I've gotten. Meanwhile, a lot of other things that used to bother me don't at all anymore.
My mom was a PE teacher and could whistle REALLY loud by using her fingers in her mouth (most of my friends would probably make some sort of joke with that statement). I remember when one of my kids was only 3 or so and tried to imitate my mom. He'd put his fingers in his mouth and "yell" really loudly in a high pitched screech. After I asked him about it, I realized that he really thought that was how she was making the noise (by yelling).