I'm really upset with you. I waited for you for hours and you never showed up. (Possibility using COULD)
He could have called me
I went out to the party, but it was terrible. It was not fun at all. (Regret using SHOULD)
I should have stayed home - I shouldn't have gone to the party
I jogged ten miles yesterday. Now I'm so exhausted that I'm not going to work ( express a possibility using COULD)
He could have jogged 5 miles