Why do you guys think English is so hard for other people to learn?

So curious. I’m confused. I’m a native English speaker and I had no idea our language was so hard to learn. I think English is super easy, I even forgot how I learned it. I think it just clicked when I was 3. Anyway I started traveling and noticed a lot of people have a hard time speaking English and it’s just strange to me why that is. What’s so hard about it? Even little kids in America can learn it. I can’t image what it’s like to try to learn English. Please enlighten me.