This reminds me of my criteria for learning: "You have understood something when it appears to be easy." The mathematicians call this state 'trivial'. It has become easy because you trained the topic until the key aspects became part of your unconscious competence. Then it appears to yourself as easy - because you no longer need to think about it.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.