Those of us who paid our property taxes on-line this year got a big surprise — a 2.3 percent “convenience charge” for using a credit card to pay our taxes through the county Web site. (And, in finest Dallas County tradition, the site is down this morning, the deadline to pay property taxes.) Why a surprise? Because the county didn’t have the “convenience charge” in either of the last two years.

Choose your adjective to describe this outrage. Mine is reprehensible. Dallas County, for reasons known only to the county bosses, is treating a credit card purchase as if it was a credit card cash advance. I can spend thousands of dollars on Amazon and pay for it with a credit card, and impersonal, corporate Amazon treats it as a credit card purchase. But do it with Dallas County, which my tax dollars support and my vote empowers, and I get gouged.

I don’t know why the system changed. When I calm down sufficiently and can act in a responsible, professional manner, I will call Dallas County for an explanation. If I get one, I will update this post.

Otherwise, I think I’m going to pay my taxes in person next year — with 4,000 dollar bills and an Advocate video camera on hand to record the fun and excitement. Two can play the convenience game. And county tax-assessor collector John Ames, whose behavior in the Bruce Sherbet fiasco borders on despicable, has lost a vote.