Vayishma Moshe es ha'am bocheh l'mishpichosav ish l'pesach ohalo... (11:10)
A really nice Chasam Sofer on this pasuk: When a Jew is in pain, he doesn't suffer alone. His friends come to console him, his neighbors and family come to give comfort and share his suffering. The sin of Bnei Yisrael here was that each person cried "l'pesach ohalo," sitting by his own doorway, concerned only "l'mishpichosav," for his own immediate family. When Jews don't feel each others pain, when each person cries only for his own tzaros and his blind and deaf to his neighbor's situation, that's a real tragedy.