Personally i find it annoying, and very unprofessional. If i have 6 email addresses and i add them all to one gmail account, the recipient should not be told what my primary email address is! What if its private or personal?
Anyhow, after many years of complaining it looks like google is finally stepping up!
Our team has heard loud and clear that you would like an option that
does not include the "Sender:" field for sending mail via your other
address. To address this problem, we're working on a long-term
solution that will allow you to send mail directly via your other ISP
from within the Gmail interface. Since the mail will be sent by your
other ISP, Gmail will not need to authenticate the mail using the
"Sender:" field, and your Gmail address will not appear in the message
headers.
This feature won't be ready for a little while yet, but I wanted to
let you know that it's on the way. In the meantime, I and the rest of
the Gmail team appreciate all your candid feedback as we strive to
improve Gmail.
Thanks for your patience,
Sarah
Gmail Guide Yellow
Full post from gmail team:
CLICK HERE TO READ