Citigroup 's (NYSE: C) marketing team must think I'm stupid. "We are making changes to your account terms. These changes include an increase in the variable APR for purchases to 23.99%," reads a note from the company that I received last week.

But that's not the worst part. This is:

As a valued customer, you have the ability to earn a special rate that is below your current purchase rate if you accept these changes .

The bold text isn't mine. Citi included that in the letter it sent. So you'd think the offer to follow would be pretty sweet, right? Wrong. The terms are:

And you call me a "valued customer," Citi? Geez. How about you just steal some beer from my fridge instead? Maybe kick my imaginary cat? Egg the house? Anything other than this whopper of a rotten deal.

The non-offer offer
What's most troubling about this so-called offer is that it isn't really an offer at all. Rather, it shows a striking lack of attention. We don't carry a balance on this card. We never have. Instead, we use it to charge a modest number of business expenses each month, earning Hilton HHonors rewards points for each purchase.

Citi, in effect, is offering me an interest rate I don't need and won't use. Nothing of consequence, which means I'm no more a "valued customer" than my 4-year-old son.

So why did this presumably top-drawer bank waste the postage? I posed the question to two of the Fool's top banking analysts, Morgan Housel and Matt Koppenheffer. You won't like their answers.

Living off the ignorant
"Citigroup knows exactly what it's doing here," Morgan says. "It works. People fall for this stuff hook, line, and sinker. It's a sad truth, but the majority of borrowers don't have the financial literacy skills to understand they're being hosed by a lender's offer."

Matt has a similar perspective. "In the end, the credit card industry really thrives off of people simply making bad decisions about their personal finances -- namely treating short-term revolving credit as longer-term financing," says Matt.

In other words, just like Bank of America (NYSE: BAC), JPMorgan Chase (NYSE: JPM), and Discover Financial (NYSE: DFS) do with their cards, Citigroup hopes you'll take the bait and become a profit generatorfor the bank.

My advice, though, is to stick it to lowball credit offers with awful terms by demanding more than they're offering, because better deals areout there. I grabbed one from American Express (NYSE: AXP) over the weekend.

Anatomy of a credit multibagger
Amex likes me, and for good reason. I've been a customer since 1991, and my wife and I charge the majority of our monthly expenses to our green card. We do this because (a) we've been in debt, and having a card that's due in full each month enforces ongoing spending discipline; and (b) Amex's Membership Rewards program helps us fund exotic vacationswe wouldn't ordinarily be able to afford.

As of today, we no longer use the green card. We've upgraded to what American Express is calling the Premier Rewards Gold card. Why? Because, by my math, we're going to earn at least a 500% return on our incremental investment. Continued...