From the very beginning, one of the few annoying things about Gmail for many users was the way it grouped messages. Unlike just about any other e-mail application or service, Gmail put all messages in an e-mail thread into what the company calls "conversations."
What that meant in practice was that it was often difficult to determine which message was most recent.
Now Google has promised to offer a "standard" option within the next few months, which should work like conventional e-mail.
That Gmail's "conversations" approach to organizing messages is bad is, of course, only my opinion. Many users love it, and consider it an "advanced" way to do e-mail.
My own view is that it's a little more time consuming, and a little more confusing. With a "standard" approach, whatever the person said last is on top, and the rest is below. But with Gmail's current approach, sometimes the most recent message shows up at the bottom. I think it has something to do with the combination of Gmail's attempt to create a message thread, plus some other application's weird approach.
Also, Gmail is always rolling things up, and you have to click "Show quoted text" to see it. This hunting for messages and clicking to reveal parts of the conversation just added time to the already time-consuming process of slogging through e-mail.
What's your view? Will you use "standard" view or "conversations"?