I'm going to purposefully slow down the wifi
Is there a reason why you want to slow it down?
So many people are watching movies on Netflix. I think they are selfish to use it at the same time.
You shouldn't be trying to slow down other people's wifi on purpose. It's rude and people will think you're the selfish party here.
I'm just slowing it down temporarily.
Slowing down the wifi isn't going to accomplish anything except making everyone else mad at you. If you have an issue with the way they're using the wifi you should talk to them about it, not intentionally make it harder for everyone to use it.