In my experience most problems with boundaries do not lie with other people. They lie with us. We invite people to violate our boundaries and then get upset when it happens! How bizarre when you think about it. We don't have the skills or the courage to do something about it and yet it's all so avoidable.
When we see well behaved children, we know they don't operate from a 'be seen and not heard' place. More they know what's ok here and what's not. This has to be learned and as adults if we have not learned it, we must be taught. There is a linear continuum I believe that explains this best. It is as follows:
AGGRESSIVE -ASSERTIVE -SUBMISSIVE
If you know where you tend to default to on that continuum then how you manage boundaries will be reflected there. Let's explore the positions. People who are Aggressive tend to violate the boundaries of others either wittingly or unwittingly. This can manifest through having staff work late. Nobody leaves the office before you do. Macho values (lunch is for wimps etc).
People who tend to be Submissive can be cannon fodder for the Aggressives. They can behave like victims, always put upon and wanting things to be different but never taking a stand on important issues. Plainly such people need help to express themselves and state their own needs in a mature and consistent way. Finally there's the happy camper group. This cohort seem not to be flustered and are comfortable speaking up and challenging when they have issues. Why can't more of us be like the Assertives.?! Easier said than done. You need a strong sense of self-worth and high self-esteem to have this as a default, Yet this is where we operate best. In Coaching parlance we refer to this as Adult to Adult communication.
These positions can all be modified, learned and unlearned. If you operate on either end of the spectrum then you most likely need to get some Professional help to enable you become less aggressive or more confident. This will allow you CHOOSE Assertive as your default. Then you'll notice people treat you different. You know why..? You have BECOME different. A price well worth paying!
Have you ever noticed how positive language reflects these positions..? Strong people are referred to as 'centred' and 'grounded', 'comfortable in their own skin' and unapologetic for their opinions. That's ALL of us when we play to our true potential.
-Hope something in there helps you. This thinking has helped me enormously over the years.