I'm really smart and take it for granted and I do good in school but I don't try that hard so I get A's and B's even though I could be getting straight A's with a little more effort.
Does it have to do with being lazy?
Yes, it has to do with being comfortable
You should work to the best of your ability. If you waste your time in school, you will stop yourself from learning all that you can.
But I want to play video games with my friends. So what?
It would be great to do better in school if you know that you  can. You can always make time for your friends, but you should proritize your school work.