I am quite frustrated with the way gmail web application deals with email created in response to an email. If you reply or reply to all it does not put information into the email to show who was on the previous email or when it was sent, etc. If you forward an email it does. You also cannot have both a reply and a forward email at the same time.
I often get an email that has 5 of the 6 people that need to be involved included. I want to reply to all, add person number six, let everyone see when the previous email was sent and who was involved.
It is also common to need to both forward and separately reply to an email. I would like to be able to start both of those emails and drop in the relevant additional information as I collect it. The one or the other limitation makes it necessary to track emails I need to send in a separate list.
To me this is logical, methodical, basic functioning available in email since the last century. I continue to be puzzled on how to create a workflow pattern when basic operational functioning disappears.

