Then why are my Cocoa Puffs always on floor level?

I use it because I don't want to interact with anyone and do any small talk. Also, most lines with a cashier are long and/or customers have full carts, and not many people in line for the self-checkout, so the self-checkout process is often quicker since you're not waiting on others to finish.

Also products aimed at kids like candies or any goods with colorful toy freebies are placed at kid's eye level

This is NOT true. My local supermarkets typically have massive signs for Flour, Sugar etc to help you find them. What is true is that these items are well inside the supermarket making you walk past other items that you might be tempted by.

Actually, fruit and veg are in the beginning so you feel like your already got some healthy stuff in your basket and not feel bad to put some less healthy stuff in it too.

Our supermarkets do not change every few months.

I thought it was at the back to draw customers deeper into the shop?

After the self checkout machine thanks me for shopping there I always say, " Thank you robot checkout lady".

Lidl has these smaller carts. They are maybe half as big. I love them. Mostly because I am a small person and I feel dwarfed by the bigger ones.

Not at all. Grocery stores are food storage places. It's for energy efficiency and product protection. Windows let out heat, greatly affecting temperature control, which 100% of supermarkets need to track. Products not sold fast enough fade or rot in sunlight. Windows also limit space and layouts. Windows would help customers but they're bad for the actual business. There's studies that explain it.

One research says it does, another says it does not. It's probably just a side effect. Actually, everything fresh (fruits, meat, fish, bakery) are together. Often they are also the most staffed, and visible. It's just more pleasing than aisles full of inert goods and skittish clerks. Moreso, fruits and veggies are the ones that require the least backstore equipment (oven, grinder, fridge) which is why the other fresh are more often against the back wall..

the local Stop & Shop (big grocery chain in the New York/tri-state area) has the deli counter on one side of the store (along with the bakery department), but the packaged bread aisle (where most people here get their sandwich bread) is literally the complete opposite side of the store. The condiment aisle is somewhere in the middle (not near either the deli, or the bread). So this one I can confirm from experience.

$500 in their whole lifetime? Wouldn’t that logically average to like one cent per purchase? You SHOULD check your receipt to make sure you weren’t double charged, though.

This is a tactic? It's just a complaint.

These are on the decline. There used to be loads of sweets on the checkouts which kids would try to sneak into the shopping and these were stopped due to complaints. There now appears to be even less of the stuff that they put there to replace the sweets.

In my country the original price has to be written too

There is nothing wrong with trying to increase sales. As long as nothing is done deceptively [like bait and switch pricing] the burden should be on the shopper to make intelligent decisions. Make a list. Stick to it. Do the simple math.

I never realized McDonalds is considered a supermarket...

All checkouts are near the exit. The self checkout is closest because it's supposed to be limited to less items than a full cart, hence quicker exit. It's not a trick. A cart full of groceries checked out in a lane takes longer than one or two items in the self checkout...

We have a lot of prises like 1,99€ in Germany, because 1,99€ seams much cheaper, than 2€

I can say my purchasing habits aren't that affected from touching stuff.