Why doesn't the power connector on my thunderbolt display fit in my 13" macbook pro? This is beyond irritating and I can't find any info.

The magsafe connector for my new 13" retina display MBP is different than the one for my old (12 months) 15" MBP and is not compatible with the 27" thunderbolt display.

I could understand if one were older than the other, but I literally just got the new thunderbolt display and 13" MBP from Apple yesterday and the magsafe power coming from the display does not fit into the magsafe connector on my notebook.

What gives?
Your Thunderbolt monitor has a MagSafe Connector - your MBP has a MagSafe 2 Connector. Apple now supplies a MagSafe to MagSafe 2 converter with the display (check the packaging - the adapter is small). If you are missing the converter, check with Apple - they should give you a replacement.