Why is my Mail running so SLOW?

I have a new MacBook Pro with Retna Display. It is supposed to be the biggest and best laptop Mac has to offer. Mail is not working properly. It is slow. Sometimes it takes several seconds to move from click to item actually responding. When typing, I am several words ahead of the type showing up in the email. It is SLOOOOOW. Please help. I'm frustrated. No help from Apple for this matter, which amazes me because I see many other people having the same problem with Mail.