I hate this!!!!

I was just logged on this computer(my dad's), when I decided to play DotA to pass the time. My mum spotted me and told me to stop playing and use the comp to read instead. I tried reasoning to her, telling her I did not play anything on any PC since yesterday, so like"gimme a break!" She said, "No, no. Stop playing and start reading". Pretty contradictory cuz whenever I used the PC to read news or buzzes on the 'Net, she told me to "Stop using the computer because u're just playing games!" I mean like WTH, I'm reading peacefully and she had to stop me!! I'm not playing any games and that's what I get whenever I get my hands on the computer. All she cares is that if I'm sitting in front of the PC monitor, it's enough to qualifyas I'm playing games, so no need to check on me and just tell me to stop.