Budgets for Dummies

Does anybody else keep a meticulous budget like I do, swearing that every penny is accounted for, only to continuously go way over the budget! And then I can never figure out how we go so far over. It's like the missing socks in the dryer mystery!

The only thing I can figure is that I so desperately want to believe we spend less, so I round down in my figures for my budget. It's either that or my husband...he's a shopper. Could be those secret donut runs he's always making.

Does this happen to anybody else, or am I just lame at math?!?!