Sentence-initial transitions

I know that many elementary teachers say "Don't use "And" (or "So" or "But") at the start of a sentence. My elementary teachers told me the same thing. But there are a lot of English teachers in Japan who just parrot their own elementary school teachers' admonition without really understanding the reason their teachers told them that. The question is "Why do elementary teachers tell kids not to use "And" at the start of a sentence?"

Elementary-age kids are not sophisticated writers. Of course. They are learning the conventions of the language. They'll write things like: "I went to the mall. And I bought some shoes. And I ate ice cream. And then we played video games. And it was fun."

In other words, they are writing like they speak. And as you can see, the "And~" at the start of the sentences becomes annoying and redundant. That's why teachers tell kids not to do it.

But that doesn't mean that it's always wrong to use "And" at the start of sentences, just use these sentence initial conjunctions judiciously.

Don't believe me? Google it.