A tidbit from James Scott Bell's book Plot & Structure. "Most often, the best way to create a memorable scene is to intensify the clash. Two characters oppose each other. They have the strongest possible reasons to do so."
It took a long time for me to internalize this lesson. In my earlier stories, there is a lot of physical movement of the characters, as a substitute for plot movement. Similarly, conflict for me usually meant physical action. Only gradually did I develop the skills to move plot and conflict in a non-physical manner. One of the strongest tools for creating memorable scenes is to give your characters--even your sympathetic characters--differing motives and goals in any given situation.