lets not forget, In season 1. Shane told rick dont leave the camp for the guns, rick leaves anyway and how many ppl died that night? andrea sister would probably still be alive if they all stayed.
Shane told rick sophia was dead
Shane showed herschel they are not ppl anymore.
Rick would be dead if Shane didnt cover his hospital door with the bed.
Rick risked everybody life by not telling them they are infected.
Shane forced everybody to carry guns on the farm again. if he didnt they would of all been dead when the walkers came to the farm.
and now Shane got himself shank....then shot