At times I feel angry in myself for being too courteous and accomodative to people to my detriment. I end up saying yes even when I want to say no, and find it tough to stand up for myself until I get very bitter and then things become worse. I run a business and people often take me for granted specially those who know me, never pay me on time out of carelessnss. I make up my mind to remind them but when the time comes, I find myself unable to do so. Is it a personality issue. How do I deal with it?
It seems that you have not yet established healthy personal boundaries. The absence of clear, appropriate boundaries inevitably makes it hard to know when to accommodate others, and when to stand firm. And when other people perceive this—whether consciously or unconsciously—they all-too-frequently take advantage of the situation. They are not necessarily being nasty when they do that; self-interest is simply human nature.
Sometimes we can develop healthy boundaries on our own, through deep introspection in the light of our own understanding and sincere aspirations, and perhaps you can do that. My recommendation, however, is that you engage the services of a competent professional life coach or psychotherapist. Such a person should be able to engage you in an illuminating question-and-answer process that will enable you to sort this out.
Boundary issues are too important to leave unresolved, and you might be surprised at how the clarity you gain through resolving them can also lead to greater clarity in seemingly unrelated areas of your life. It is well worth your time and expense.