A fine line

It is certainly not a criticism, just just one of those observationisms (and something that keeps confusing me on walks) but

I appears live in a city with:

a) An awful lot of people who walk around the streets mumbling, making sudden shouting noises and talking nonsense to themselves and

b) An awful lot of people who walk around the streets mumbling, making sudden shouting noises and talking nonsense into mobile phone hands-free kits.

Sometimes it is very difficult to tell the difference between them.
It is a great leveller.
Hurray!