Credit where credit is due?

My wife and I were enjoying the post Thanksgiving shopping extravaganza when I was informed by a very nice young lady behind the counter at a local retail establishment that my credit card had been rejected, refused, not accepted, etc. Ouch....I hate it when that happens.

Of course, as soon as I returned home I called my local banking establishment to find out what was wrong. I was informed that my credit limit for "per day" purchases was $550 and my shopping totals had exceeded that. (Okay, I am sort of embarassed that I would be spending more than that in one day....but it is the holidays after all!) The nice young man on the phone gladly increased my credit limit for daily purchases - problem solved.

Since my wife and I each have a card that draws on the same account, I asked if the new credit limit was "per card" or a "combined total"of our two cards. I was quickly informed that it was "per card". Being the helpful guy that I am, I inquired if I needed to have my wife's credit limit raised as well - I would hate for her to have the same problem I did.

I was then informed that her credit limit per day was $X,XXX dollars!

Now I'm wondering how the bank knew to set her limit at basically infinity and mine at $550? And what does this all mean in relationship to the phrase "one will receive credit where credit is due!?"