I thought Ikea was a scary place on a Saturday. I was wrong. Ikea ain't nuthin'!
For scary, just go down to the local grocery store. Too much stuff packed into too small of a space with very narrow aisles and mobs of people welding shopping carts who will suddenly stop in the middle of your way to chat with each other.
Add to that your own long list of things to purchase and a list of words in German that you should be looking for and it all adds up to an unpleasant experience with shades of claustophobia.
I never much cared for grocery shopping in the United States. Just one of those "get it out of the way activities." And we generally shopped on weekends, when it was busier. But in the United States most grocery stores are open 24 hours a day and on both Saturday and Sunday.
Imagine taking all of those shoppers from Saturday morning through Sunday evening and squeezing them into an 8-hour period. 'Cause the local grocery stores here are only open from 8 am - 4 pm on Saturdays and closed on Sundays.
Grocery shopping is now a mid-week activity. Preferably in the morning when there are very few people.