It’s not fair for you to say that Thai people are rude, selfish and bad mannered in general. I’m a Thai and I disagree with you.
This is how I see it. Thai people, in general, obviously have different educational system compared to other part of the world. They’re not educated to think by themselves too much hence that’s why they are more respectful towards elders.
At first I didn’t understand why they are the way they are but then I thought about what I learned at school when I was a child. I realised that they’re not used to thinking a lot. They were taught to memorise or recite things most of the time, especially in government schools. No critical thinking, no sharing ideas in class, etc. Teachers were there to teach and what they teach was what I could read myself in the book!
So Thais in general are not lazy, rude, selfish. They’re just not used to ‘think’ about anything. And it’s not because they don’t want to BUT they don’t know how to. It was hard for me to believe but it’s true!