How do the plays of All My Sons and The Crucible portray the consequences that occur when individuals pursue their own personal good at the expense of the common good of the group or society?

These are pretty different plays. I suppose Keller, like Parris in the Crucible, is all about himself. Keller is willing to sacrifice pilot lives by sending over defective airline parts. When the truth comes out Keller lies and places the blame on Steve (who was told by Keller to send parts). Similarly Rev. Parris is quick to lay blame for the witch hysteria. Parris wants to protect his own interests. He is a "man of God" and someone needs to take the fall for the witch hullabaloo. In particular Parris wants vengeance on John Proctor for questioning him. All My Sons never reaches the hysteria of the Crucible but the some of the themes that you mention are relevant.