Brummie,
I'm afraid that you have just given away the fact that you are most definitely living with a lady.
You see, the behaviour on which you are commenting - and objecting to BTW -is definitely a girlie one. Girls do insist that they want the top of the milk, and will therefore open up another bottle even though the one in the fridge is awaiting consumption.
The same thing happens with butter, biscuits and bread. They want it to be FRESH! So, they discard the half finished open packet of whatever and open a new packet/bottle/ box.
Englishman.