I feel lazy to study for exams so I want to reward myself everytime after studying for eg : playing video games only after studying something. Is that haram because Im making my own rule or a law by not playing games until I study something and I've learned man made laws are evil.
I am going to tell you something very simple. "If ain't heard, it ain't heard". If you haven't heard from your parents or in the Masjid about something, then most likely it isn't wrong.
For example, a question earlier came about if they have committed shirk just by "thinking" about jins and contacting someone who just spoke about it with his friend who didn't know, but no action was committed.
If we analyze the similarity between both questions, both yours and the earlier one, you can see how both are talking about something that me or you probably haven't heard from our Masjid Imams or haven't heard from our parents.
Disclaimer I am not advising that if you haven't heard something it is halal to do. I am talking more about the moral side of things. But it is always best to research or ask someone who would know.