Great that you held a boundary…this is not to be underestimated…it takes courage to stand firm
I like how you are pulling the positives out of this situation.
Enjoy the cheese,olives and Vardaguyn
Good for you - walking away was better than saying something that later you might have regretted. I think you had the higher ground here.
So the fishmonger gave you a bit of fun, even if the day did not go well!
Dealing with this: First, look back at what happened. One thing was good - the fishmonger's reaction. Second, put it in context - they have the issue of profit loss; but you can buy those things elswhere or save your money for another day. It was a shame but soon someone will benefit by being offered the baker's job. Next, sit down with a cup of tea and bun [or whatever treats you enjoy], take a breather whilst planning nice stuff for the rest of the day -preferably in writing so you can tick the list as you do those things.