As if you didn’t have enough people telling you what to do, here I am ready to teach you a little email etiquette.
Read the email completely before you reply all.
Think again before you reply all.
Does the email speak to whether or not you should reply all? If, it does speak to this and it specifically asks you to “not reply all”, do not reply all.
If, after reading, thinking and triple thinking, you determine that replying all is the best solution: think about what you say before you say it. And,