I was at my first office job in a small Asian company. My boss once say to me: You would not be able find any job with your broken English and you are so lazy. Even though I was working 60+ hours per week and do not even dare to take any sick day or vacation. I was getting yelled at for take half sick day to go to immigration office to get physical check. I know I have to get out of there, I took some online coding class and find a job pays more than double and work less than 2/3 of the hours.
I quit with a smile and showed him my new offer letter. He was not ready to let me go, and said he would give me extra 10,000 than the offer letter for me to stay. But at this point, its not about money anymore.