but I'd weep for joy if my income were only taxed twice.

Let's see, when it comes to direct taxes on income:
Federal income tax
Social Security tax
Medicare tax
State income tax

Throw in the other taxes:
Property tax
Utilities tax (electricity, gas, water, sewage)
Vehicle use tax (at least here in Colorado)
gas tax
Phone taxes
Sales taxes (city, county, and state)
And never forget the pass-along (stealth) taxes that businesses pass along to their customers in the form of higher prices

And without a doubt a host of others that don't come to mind at the moment. Each year, the total comes to well over $40,000 for my wife and myself. Double taxation? In my wildest dreams!