It's a command line interface, not plain English. What's ugly and inconsistent about the git log command as was quoted in your reply?
> I've got better things to do than become an expert on needlessly complicated software.
As a software developer, I have to read through a lot of documentation to be able to use programming languages, SQL, data stores, unix utils, etc. I don't see why it would be any different for a VCS.
I think the actual issue is that people aren't willing to read through the documentation to understand what a command does and what options are available.
As for the command itself, the -p switch shows the diff associated with each commit shown with the git-log command. origin/master represents the upstream tracking branch of the master branch (most likely the base branch that the person is working on). .. represents a range operator and HEAD repesents the commit that's the latest commit on the branch on the local machine.