The plague of darkness serves two functions in terms of both maintaining and highlighting the difference between the Jews and their Egyptian taskmasters.
What does the first pasuk repeat the words "hamishkan mishkan haedut," when it could have invoked either of those expressions?
To state that the start of the parsha follows on the end of the previous one is obvious--why does Rashi do so?
Why does Rashi detail specific events that Yitro "heard," when the Torah itself tells us that he heard "everything…"?
Why does Rashi tell us the direct translation of the words v'lo nacham, and then explains the words derekh eretz plishtim by signaling that he is omitting any of the many midrashim on the subject?
Why does the Almighty seemingly introduce Himself to Moshe Rabeinu again at the beginning of the parsha?
The strange placement of Yosef's name among those who came to Mitzrayim signals his unique character as a tzaddik.