Further to the question of "I sat there" versus "I was sitting there": both correct, not always interchangeable.
"I sat" may refer either to the action of seating yourself, or to the duration of your sitting: "I sat there all evening."

"I was sitting" refers only to the period after you seated yourself. Returning to my seat and finding it occupied by someone else, I would not assert my prior claim with "I sat there" but rather "I was sitting there," or "I sat there first." The simple past "I sat there" could imply my occupation of that seat was over and done: mere historic information.

You could with only a slight change of meaning substitute "was sitting" in the phrase "I sat there before anyone else could take that seat"; while "was sitting" would make a great difference to "I sat there immediately when Dad told me." The past progressive (?) tense "I was sitting," instead of telling about the action itself, describes a scene after action ends.

I'm not getting this out of a textbook: I'm describing how our language, as I see it in use, gets ideas across as faithfully as possible. Is it any more pedantic than discussing modes and harmonies? Pedantic is making arbitrary rules and telling others to follow them: prescribing, not describing.