I saw a vision telling me setting myself to silent mode

On a bus I saw a sticker which inform us of manners of mobile phones on the car.

It was written in Japanese and English.

I found myself reading out loud the first few word of the notice written in English.

Suddenly I saw a vision of some additional words on that sticker.

I'll write the notice in blue letters and the vision in red letters.

Please set your mobile phone (and yourself) to silent mode and refrain from talking on the phone (and to yourself).

And few people but me talk to myself on a train, bus or subway, whereas I saw sometimes someone was talking on their phone.

It was as if someone were telling me that I need to acquire the skill of setting myself to silent mode.