Many of us we please people and we feel sorry for them, we are afraid of saying no, and we expect either could end up the relationship or loose a job.
But no is a word like other words, you have to change the habit of feeling sorry while saying no, why? because you saying no will open a serious door for you to pass.
Say no because you respect yourself and you want to more of you to shine. No means love because the truth sometimes its bitter so accept it and never feel guilty, no is just a word and you love.