Ever wandered why people treat you a specific way? Where is it coming from how they treat me? Is the behavior towards you exactly the behavior you want others to act like or rather not?
Well, most likely they sense how you treat yourself. Do you take care of yourself and your body? They will notice and ask you if you want a glass of Cola or not (super simplistic example).
If you are always the person who changes her mind to go clubbing and joins the group last minute, well, your friends will most likely call you and ask if you want to go out again. Or maybe cancel, bc no one was sure you show up anyways.
You can also set your own boundaries not only with actions, but simply expressing your borders. 'Hey, it was not cool to let me wait for so long and then canceling. It's fine when things changed on your site, just let me know earlier.'
Consciously or unconsciously, you will set the boundaries of how people interact with you and not only on base of how you are with them, but also how you treat yourself.