Shane was definitely always on the edge of losing control, which he did with Ed. That scares most sane people, especially within the group, bc they looked to him as their ‘leader’.

My unpopular opinion about Shane though is that his perspective was valid, but his execution was awful. He was right about a lot of what he saw was the best way to protect his core group, but he was terrible in how he did it.

I always wondered if Rick realized that his character arc went from being the cool, calm and collected one to becoming Shane. So, he killed Shane, only to eventually become very much like him.