My memory is not as good as it once was. Especially involving numbers. (I once was REALLY good at remembering phone numbers. Not a Savant (Rainman) level of knowing phone-books, but any number my mother ever needed (she would tell me to remember a number, and I could memorize the pattern of the numbers on the dial-pad.)

After the operation, I can only remember things that I concentrate on, and tell myself that it's important. i.e. I know Wednesday is garbage day, but I don't know what day it is today. Or another example, I know my wife's birthday is June 2nd, I just can't remember the year.

I used to be weirdly good at memorizing numbers when I was a kid too, but that ability faded for some reason as I got older. Not sure how sudden of a loss it was for you, but perhaps your memory might've changed somewhat anyway as you got older, even if you hadn't had the surgery?

That is completely possible. The sad fact of this incident in my life; I will never know if some behaviours are because of the tumor or not. It really is a Nurture vs Nature toss-up for me. =)