Rule number one: there are no rules. A ‘mistake’ may not necessarily be a mistake if it helps convey the message or story or feeling intended by the photographer. I can easily think of multiple examples that go against every scenario described below. That said, for the most part, I’ve found these ‘mistakes’ to hold true. And if you want to achieve something very specific, then you either won’t be reading this article in the first place, or you’ll know when to bend the rules. The general viewing public probably has some preformed opinions of what is right/good, but these are born out of as much ignorance as conditioning by companies trying to sell more software or lenses or something else. There are rational reasons why these opinions may not necessarily be right in the context of fulfilling creative intention.