I have a younger sister who clamors for me to play games with her every day. I hate her. What should I do?

The child is too young to be sensible. Why should you compete with her? You can lie to her with some white lies and tell her that my sister/brother is busy playing by herself now, or help her find a fun single-player game on the first floor. Either leave when you see her coming, or don't turn on the computer.

I also have a sister who wants to play games with me. I usually use the above method. How old is your sister? My sister is 6 years old.