We use this term "personal data" so much. But what IS data? If I happen to know that you like cheese sandwiches, is that really data? When did we decide that k

We use this term "personal data" so much. But what IS data? If I happen to know that you like cheese sandwiches, is that really data? When did we decide that knowing something about somebody else was such a big deal? It's whatever I want it to be, and I should be able to change my mind about it. It's not hard.