The keyring stores passwords and gives you access to things that require
more security. It should not be seen as a pain, but seen as a security
measure meant to put your mind at ease that Ubuntu has your back covered.
With Lucid the *buntus became more security conscious. Drives that were
previously mounted by default with no password became subject to increased
permissions that often require a password to access them. Some of this may
also have to to with encryption which became available at the time. It seems
to a package deal. You can't have encryption with lax security. It isn't
just with Ubuntu BTW. It happens in Kubuntu and other distributions such as
Fedora. I am not sure about Mint. If it bothers you then you may have to
look elsewhere, but I think that improved security is here to stay.