I hate to get into a flamewar but 90% of the themes they are so proud of break basic usability guidelines: Too distracting, not enough contrast between read and unread items, ignoring color theory for the meaning of colors used in the interface, etc. Drives me crazy.
Edit:
And as I posted to my Tumblr (http://ajh.us/GmUI) just 5 days ago:
> Today I opened a Gmail window. At the top of the screen, I saw a yellow message beginning, “Hey, this is important! …” I never finished reading it because I had clicked something else (a message) and the supposedly important message disappeared, never to be seen again.
> So the Gmail team either
> 1. Lied about the importance of the message, or
> 2. Totally failed to make me actually read it.
> Not so impressive UI design.