Being assertive

I found out that despite the huge amount of people calling me assertive, I am not assertive at all. And I am quite disappointed by the fact that I cannot be assertive when I need to say "No!" to several dishonest, bloodsucking parasites that exist around us. I know how I should set my mind but I don't know why I am not doing so.

1. Troubles only exist when we see it

2. Never worry so much for what has not happened

3. Always know our own limitations

4. Never try to please people more than what we expect from people.