My sister asked me to buy tampons and I refused.
What is the reason behind not doing her this favor?
I hate how she is always bossing me around.
Have you tried talking to her about how you feel? Maybe she doesn't realize that you feel like she is being controlling. You should both be willing to help each other out when possible as you are family
Stop talking to me if you cannot telling me to do this.
I am just trying to help you improve your relationship with your sister. Don't you want her to help you when you need it in the future.