Destructive Lies
I have watched the series twice through and am on the third go now. It struck me how so much trouble is caused when people lie to their friends.
One example is when Bobby talked to Otto. He told him he had been sleeping with Otto's wife. When Otto asked if the club had taken out the guy who killed her, Bobby felt so guilty about causing Otto pain he lied and said Georgie had been killed, even though the club was keeping him alive for a while to use him to prevent Charming Heights from being built.
Otto found out that Georgie was still alive. That pushed him over the edge and he agreed to work with the feds in the Rico case. Because of that, Tara visited him in prison and was implicated in the murder Otto committed to reverse RICO.
There are plenty of other instances like this.