Colloquialisms

Johonnas: "A month ago I never would have thought that I would be here... walking my bike... to go rock climbing.. with a student from America."
Angie: "...Well who does think that??"Leo: "Guys! How did you know what I was thinking last month!?"
Johonnas: "Sometimes, fate pleasantly surprises you."

American English vs. German

American English:

My knight in shining armor.

German:
The dream of my sleepless nights.

American English:
It's raining cats and dogs.
German:
It's raining little dogs.

American English:
Beating around the bush.
German:
Walking around the hot porridge.

American English:
I have a song stuck in my head.
German:
I have an earworm.

American English:
Entanglement or telepathy.
German:
Different people same thinking.

American English:
Fight fire with fire.
German:
Shooting at flies with cannon balls.

American English:
I lost my train of thought...
German:
I lost my red string...

Some Popular "Unfriendly Friends" (False Cognates)

hell = light
mention* = people
damit = with it/with that
war = I was

* Spelled like English pronunciation.