> "and therefore..."

I find that considerably less irritating than starting off a reply with "So". Those who use it by conditioned reflex should be obliged by law to replace it with the directly equivalent "Therefore", and to have to watch their listeners' faces.

Its original form, which seems to have died out, was short for "You didn't go to Stanford as I did, so let me rephrase it this way ...." This ex-cathedra prefix was followed by a three-second pause, during which one could hear the creaking as the speaker's language was wound down to street level.

--- Oops: *bzzt* "Repetition!"