How are you able to say "NO!"?

Dear diamania, I am normally very tactful and accommodating. I will try my level best to do it, but at times in life, we have our priority too. I am now married with family. Family have to be the focus, the priority. So, if I need to go home to fetch my son to school, then I cannot say 'yes' to fetch another person to elsewhere unless he willing to wait. So, we should learn to say 'NO' when it is necessary. Just remember we cannot please everyone. I remembered helping someone else, and I missed the opportunity to invest in some bonds, thus losing the opportunity to earn money :( Cheers and take care.