this is the wikipedia recap of "What have i done to deserve this?": Following their sexual encounter, Meredith and George avoid each other at work. George is angry when he thinks Meredith told Alex that she slept with George. Alex just figured that they must have slept together and only said it to Meredith as a joke. George, at the hospital, ends up falling down a stairwell and dislocating his shoulder. Frequent heart patient Denny is readmitted and grows closer to Izzie, causing Alex to be jealous. Although Bailey is on maternity leave, Addison asks for her treatment after exposure and an allergic reaction to poison oak in an especially uncomfortable and personal place. George flashes back to the previous night with Meredith, when she cried out of regret while they were having sex, and he moves in with Burke and Cristina. Throughout the drama, George catches the eye of Dr. Callie Torres, a resident who had heard of George's 'elevator heart surgery' exploit. At the end of the episode, Callie gives George her number.

I dont see the connection

This episode showed us flashbacks to show whar happened that made George mad at Meredith.