I kinda agreed with Sam, until it came out that hint of jealousy in his "What makes Adam so special?"... That's where he lost me. He was right that being a Winchester is a curse on its own and that he deserves to know how to protect himself, but I didn't like that he was teaching him to fight just because he felt it was unfair that Adam got the chance to live a normal life.
Dean was quite utopic in thinking he was gonna be safe just because they got rid of ONE monster that was after him...