Forbidden

One of the first german words that I have learnt was "Verboten", meaning Forbidden".
 Still remember pretty clear the whole scene: a guy was going on his bike on a street in Blankenese and an old lady screamed it out loud in what was for me quite a surprising and awkward moment.
For quite a long time I have used it as a sort of joke, but lately I have been getting quite some feedback by german friends who consider themselves to live in a "culture of forbidden", where no explanations are given, being often just annouced that something is forbidden.
I have then started slowly realizing how many differente signs can you find on your day to day life where the most diverse things are forbidden.
I leave you with some examples:

Stickers forbidden

Smoking and any use of fire forbidden

Forbidden to enter the construction site 

Life danger - Forbidden to enter

Parking forbidden! /Not 3 minutes, not 10 seconds, not with a timer, absolutely nooot!

Putting bikes is forbidden

Forbidden to play on the private property