My big calculus (I, II, III) takeaways were rate of change, acceleration, inflection points (e.g. accelerating at a decelerating rate), and funky word problems

My big calculus (I, II, III) takeaways were rate of change, acceleration, inflection points (e.g. accelerating at a decelerating rate), and funky word problems involving filling bathtubs with a flow of water and calculating how fast the water line moved up the tub, or piling grain (cone) and measuring how fast the top of the cone was progressing upward. Mental weightlifting, heh.