If you risk people yelling at you for stopping, simply tell them there's too much yelling and drama for you.

Also if you have paid sick leave you could simply get ill depending on where you are and on union agreements at least here where I am, the employer has no right to know why you are sick. Just that you are. After a certain number of days/weeks they can ask for a doctors notice that you indeed can't work. But still the proof does not need to explain your illness. It just needs to confirm that you are not able to work. Most doctors will understand the strain of having to be somewhere where youre under this sort of pressure

“my doctor told me if I dont leave I will have a heart attack”

I am personally curious what "internal regulation" means?

I found a good opportunity elsewhere.

My friend asked me to apply for a position they say has better career prospects.

America is hiring remote workers at better salaries.

Something unchangeable at this company reminds me of my dead dog and it's been killing me for years.

"The snacks are too dry"

This damnable prison of log and ice eats away at my fibre. I find the lack of culture astonishing.

Krankenschein regelt.

Just say you're leaving for personal reasons. If they keep harassing you, can't you just.. not show up?

“ I would love to stay but a personal matter has arisen “

Or

“I was made an incredible offer I could not refuse”

Give them a boring answer them leave weird shit for them to find like maps to exotic places in your trash bin and secret coded messages in the photocopy machine

It isn't any of their business unless you want it to be so just be vague as hell. "I got another offer that is a good opportunity." "I've decided to pursue other opportunities." They'll obviously ask questions and you can just remain vague. "I would rather not discuss specific details of my new job."

Or if you don't mind them speculating behind your back you can say as something like "I've decided to move on for personal reasons." Just leave it at that and let them sit there and wonder. Is a family member sick and needs care? Are you sick? Did you get a different job? Do you hate everyone? Are you going to prison? Who knows because you aren't telling them.

I have been activated. Сука Блядь Comrades!
Будем здоровы!

A loved one has (fill in the blank) medical issue, and I have to go take care of them for the foreseeable future.

Will they find out that you quit? Would your supervisor tell them?

Also can't you just use your remaining vacations and call in sick to reduce the amount of time interacting with them?

The mothership has been signalled and I must prepare the bunker.

Say you could never find the bathroom.

Make the response about you and you only. Even referring to the workplace would be tricky. Some of your coworkers might take criticism of the workplace personally.

You’re being voluntarily committed

You’re going underground with a raf cell

You’re pursuing your lifelong dream of living on a houseboat in Miami

"I can't get any joy from the work anymore. I used to get joy from it. Don't get me wrong, the colleagues are nice and all"

Probably most of your colleagues will agree with you and nobody gets offended.

Just say: "many reasons" , and if they keep pressing you: "I'd rather not elaborate"

"My work here is done"

Is "going back to school" a thing in Germany? From what I know about that education system I'm guessing not, but in the US that's a standard answer.

"I want to move to be closer to my aging parents." - might work. If you haven't shared much about your life, it's an easy lie. And it's dull and depressing, so the odds of followup questions are slim. I hear it a lot when interviewing job candidates in our area.

I need to move to Frisia to cater for my ailing mother.