I keep finding that I don't see emails people have sent me, especially if they send two without my replying in between. The way Gmail saves messages as strings of conversation rather than individual emails makes this easy to do, I find- if you open a thread and read the most recent message, it then appears to have been read, even if you didn't see or specifically open the preceding email (if that makes sense).
Is it possible to set it up like ordinary email? I'm tempted to change email addresses because I'm so fed up with missing messages. Or am I just a dimwit?