Dick Boak and Rick Turner provide answers to frequently asked questions.
Your entire guitar vibrates when you play it: the top most of all, but even the neck and headstock are moved by the vibrating strings’ energy. Any loose part on your guitar may buzz or rattle audibly, sometimes only when certain notes are played. Parts don’t have to be visibly loose to rattle, and it can be quite a job to chase down the causes of some of these little noises.
Well-intended bits of advice that aren't necessarily based in fact might (aka myths) range from merely overcautious to downright misleading.
If your action feels wrong and the neck has been properly adjusted, it is time to look at the saddle.