The default clock would not show multiple time zones, and it's always bothered me that I couldn't get a calendar when I click on the time. This is a tiny thing that Windows provides and it makes my life immeasurably better. But I found The Clock [http://www.seense.com/the_clock/] and it does just exactly what I need.
Then I found I could not get The Clock positioned exactly where I wanted it in my status bar so I went hunting and found Bartender [http://www.macbartender.com/]. I didn't even know I wanted all the things this app can do, but it turns out I totally did want everything it does.
I'm kind of excited now.