Nothing unless you're rebasing upstream, but I think the point he was trying to make was that you should always run `git fetch` and then `merge` from there (again, there are some situations where the pull is fine IMHO).
At least that is what the docs say: http://git-scm.com/docs/git-pull
What am I missing?
if you run merge/rebase/etc on its own, it will tell and ask you about anything out of the ordinary and then there's no surprise.
again, it's all about avoiding errors on the rare cases because you developed dangerous finger memory.