Sorry but you are wrong. Thai law states that conducting any work requires a work permit. It "relates" to Thailand because the person is physically located in Thailand.

1) And what Thai law consider work exactly?

2) According to you, if a businessman comes to Thailand to rest for 2 weeks and decided to do some work for one day on his laptop (which he brought with him) then he'll become a criminal and can be taken to a jail.

3) According to you, millions of people break this law every day: they come from their countries to other country and once they reply or send an email (or something like that) - they are criminals!!!

I don't remember the exact phrase off the top of my head but it's basically a generic description to describe someone exerting energy to do something - e.g. even foreigners who want to volunteer in Thailand need a work permit to do so.

Not according to me. The law says what it says. The chances of being arrested for working one day while on holiday are pretty much zero, but technically it's still a breach of the law.

Even someone who comes for a month and works every day has very little chance of being caught or even being an issue the police would be concerned about/investigating, but that doesn't mean what they're doing is legal.

You seem to somehow think that because this law is in place in Thailand, I'm suggesting it is in place elsewhere? Why? I never mentioned any country but Thailand.

1) So if I make a coffee for myself while I'm in Thailand - I do an illegal work in Thailand?

2) Why not? That's exactly according to you. If not, tell me what it is that goes against your definition.

3) Because in !every country! in order to work you need a work visa unless this is your home country.