I can't easily recall much about Covey's Seven Habits. But I do recall his little diagram distinguishing between a person's circle of concern and circle of influence. Like all models this is open to many different interpretations: some think we should focus on increasing our influence. Personally, I think it may be better to try to constrain our circle of concern.
This comes to mind as I reflect on many of my experiences coaching people around assertiveness. When we try to set a boundary for the other, we often get anxious about how they may respond. So instead of saying "I don't like X" we get all reasonable, prefacing our remark with reassurances about our goodwill for them, and suffixing it with all manner of qualifications like ",of course I may be wrong" or ",I realise that I'm partly responsible" etc etc.
Sugar coating has its uses, but it can be a bit of a con. We think we're being considerate but actually our placatory behaviour is signalling "whatever you do, don't be angry with me" or "I'm afraid of you*". Either way, we're not really being straight with the other, and we're not setting much of a boundary at all - in fact, we're quite likely to provoke an invasion of some kind.
So it's often better to keep it really short, and take the risk of leaving the other person the task of managing their response. It's more respectful - and once you get the hang of it (I'm still practicing) it's much less work.
In improv, the short bold offer is usually the one that opens up the scene creatively. Players who go waffling on, are called "scriptwriters". Clear offers invite spontaneity and they allow our relationship to be alive.
This links to my thoughts lately about "scaling systems". When we extend our concern beyond our part of the system (and our relationship to it) we may think we're being very reasonable but we may actually be separating ourself from it and it's core quality - its life.
* Of course it may be that we are afraid of them. Sometimes we may not want to signal it - and sometimes it would be better to take the risk of saying it plain rather than signalling it inadvertently.