The "dist-upgrade" misnomer & confusion

Yesterday in #ubuntu, someone asked, "I am still confused about this. Everything claims that dist-upgrade actually *upgrades* distributions...can someone please clear this up for me"
So I told them:

<maco> apt-get dist-upgrade differs from apt-get upgrade in that it will remove obsolete packages and add new dependencies, while apt-get upgrade will not. this is necessary when upgrading from one distro release to another, but it is not the *only* time it is necessary. thus, in aptitude, dist-upgrade has been renamed to full-upgrade
<maco> apt-get dist-upgrade will only change you from one release to another if you've modified /etc/apt/sources.list to point to a newer release, but this method of upgrading is not recommended

They also asked "and if i do want to upgrade the distribution (not that i do), how do i go about that?" to which I responded:

<maco> the recommended way to change distro releases is sudo do-release-upgrade

They said it was the best explanation in the shortest amount of text, so I'm posting it here, hoping it'll make it easier for people to find. By the way, man apt-get does explain all this…just in slightly more technical terms.