I'm not sure if it's strictly Thunderbird's fault, or if it's because people sometimes reply to a random message with a bunch of people one it, change the subje

I'm not sure if it's strictly Thunderbird's fault, or if it's because people sometimes reply to a random message with a bunch of people one it, change the subject, and things go downhill from there. The fact that I'm dealing with this in three different interfaces (Thunderbird, Gmail, Fastmail) is probably not helping my sanity.