I don't want to explain to the problem too much, I always said "because the teacher like me, so I won't change."

我不想解释这个问题得太多了，我总是说“因为老师喜欢我，所以我不会改变。”

youdao

"Let me explain, sir."—"Don't tell me about it. I don't want to know."

“让我来解释，先生。”—“别跟我说那事。我不想知道。”

《柯林斯英汉双解大词典》

I can't explain it and I don't ever want to experience anything like that ever again.

我解释不了这到底是怎么回事，这种事，我也不想再碰到了。

youdao

You could use "I've already" pattern to explain why you don't want to go to Japan again.

你可以用“I've already”句型来解释你为什么不想再去日本了。

I've already 课堂 - SpeakingMax英语口语达人