I'm going to deactivate a random person's facebook account
Why would you deactivate someone else's account?
I will temporarily deactivate their account for some hours
You don't seem like you're out to cause much damage, maybe just annoy someone. Still, don't mess with other people's private things, man.
I'm only playing with their account I will totally not mess with it.
This does not sound like a good joke. It will really upset people to have their social media account messed with.