Machines … URGH!!!!!

I use to be in retail, and now I spend part of my time in a museum gift shop. Normally Machines and I have a cautious relationship at best, but today was one of those days I wanted to throw the cash register against the wall! Now I know I didn’t have a lot of sales, but according to the register, I had over $138 worth. Now I am not stupid. Math usually is a good subject for me, but the bloody til didn’t match up. I wonder if the machine never cleared on Tues. after I cashed it out. I mean I balanced perfectly in the morning and when I double checked in the evening but a few rocks and a couple of $18 dollar purchases do not come out to 138, no matter how it is sliced! I HATE MACHINES!!!!