Being overly analytical (in only the most unproductive ways) and extremely paranoid, I’ve developed a dangerous habit of dissecting office e-mails. In my opinion, the “complimentary close” is the most fascinating part — most indicative of personality and emotion. Case in point: the loaded “Thanks.”
Thanks. = I hope this answer to your stupid question prevents you from contacting me again, as I am very busy and important.
Thank you. = I hope you’re as impressed with my professionalism and multi-syllabic writing skills as I am.
Thanks! = I hope you like my message, and I hope you like me!
THANKS! = I REALLY hope you like my message, and I hope you like ME as much as I like SUGAR!!!
Thanks, = Thanks … or you’re welcome.