I just don't think 'sorry' is the same as please, thank you, excuse me etc.
Sorry, when it matters, usually comes in a situation that is tense because someone is hurt or something important has been ruined. Yes it is useful when you bump into someone but in the other situations there is all sorts of possibilities for shame, humiliation and escalating tension.
I decided not to force my ds to say sorry when we were at a big party and another child deliberately hurt him. Her father swoopped in and while I was trying to comfort ds, tried to make her say sorry. It got to the point that she was squriming in his arms and crying and shouting "No, No, NO!". I thought "Who is this charade for? Ds is upset and I want to comfort him, not wait here for an apology that she doesn't want to make." Her dad said to me "She means sorry even if she doesn't say it." And I thought, what a crock, basically! It's to make the parent feel they are doing something about their errant child.
(If it had been my ds, I would have apologised to the other child/parent, checked they were ok and then dragged him off to a corner to hear exactly WHY what he did was wrong and how upset he'd made the other child.)
My ds says please, thank you, sorry etc because I say them. Basically I tell him we say them to make other people happy. I also tell him please means you are more likely to get what you want!
Atm I am teaching him if he makes a mess to help clear it up. Once he is a bit older I am planning to ask him what he thinks he could do to make it better, a bit like StarGirl was saying. I think that is suggested in How to Talk...
Agree about not forcing hugs and kisses.