せい・おかげで: “○○ is to blame/thank!”

Introduction

This lesson is awful, and it's all your fault! I mean, this lesson is awesome, and it's all thanks to you! I mean... it's no one's fault, but it's thanks to everyone that... something something... introduction. Uhhh.

Today, you'll learn how to both blame, and thank people. ...In Japanese! Let's go!!!

～せい: Say, do you mind if I blame it all on you?

構成こうせい

• 

  Casual form verb/い-adjectiveせい

• 

  な-adjectiveなせい

• 

  Nounのせい

  Example:
  → あんたのせいだ！
  "It's your fault!”

せい is a so-called "dependent noun", which is just a fancy way of saying that it can't function on its own, and it always needs to attach to something to function correctly. This is important because you can't blame someone by simply shouting 「せい！せい！！！」. They'd be all like, "Say what???"