In England and Wales you haven't completed the offence until you walk out the store. (And even then you need to have dishonestly appropriated the item, not just forgotten it's in a pocket).

So you might have a guard following you around but they shouldn't be doing much more until you leave.

As far as I know, that’s the case in the US as well.

i would think this it's same in any country with laws, except it's walking past cashiers

Absolutely, in America we tend to assume everybody is out to rob / harm everybody else and are always on guard.

Especially if you're young, just having your hands in your pockets will get a store clerk following you around. My parents even taught me as a child to never put your hands in your pockets when in a store.

This is terribly sad.

I'll note that like many of the comments on HN and elsewhere that comment on what something is like in the US that the true answer depends on where you are within the US. With the issue it is going to vary tremendously based on which store you are in. I believe in my state at least you also have to leave the store before any law is broken, although such laws are set at the state level and so there may be exceptions.

I think the law is probably reasonable in most cases.

What's terribly sad is that shopkeepers will assume someone is stealing for having their hands in their pocket.

Interesting choice of garments actually. Wearing a hoodie in America, especially if you're a young black male, gets you instantly profiled as a criminal. Whether or not the law says you're legal until you leave the store, if a clerk called the police on you, you'd be arrested in that scenario / under those conditions.