I Found This On Reddit.

That's just the stages of using PZB
1. Mockery of the system
2. Starting to get the hang of it
3. ZWANGSBREMSUNG

 

happy

(Not my picture)

 

I dont get it

 

The different trains have different faces

 

When I was a kid, I used to think buses had happy, angry or sad faces.

Happy Bus


Angry Bus


Sad Bus

 

To me the top bus looks sad, the middle and bottom buses both look angry with the bottom one looking the angriest.

 

The top bus looks like it's about to burst into tears!