It wasn't supposed to be an everyday occurrence hearing your mother spew about the filth muggles and muggleborns bring to the Wizarding society. But with a parent named Walburga Black whose lungs matched those of a torched banshee it is truly no wonder Sirius rebelled against the family and decided to learn more about the muggles that most of Wizarding society despised.
He researched by leaving the safe zones of the Wizarding world and transformed into his beloved animagus form Padfoot which allowed him to steal and observe the ways of the muggles. From what he found out from outside his World - the muggles happened to be way more advanced than the Wizarding world and they definitely knew how to have fun.
He collected magazines, cigarettes, cameras, music, etc. and even changed the colors of his room using muggle paint just to spite his family because of their naivety.
He didn't want to understand why the Wizarding world thought themselves superior to the muggle world in every way, shape, or form but as Walburga scratched her lungs belittling him and his learning muggles phase - he pulled out a cigarette, flicked the lighter and started to smoke.
"And- WHAT IN THE WORLD IS THAT?! PUT IT OUT NOW!" Walburga screeched.
"Not in this lifetime." Sirius commented as he stepped out of the room and eventually out the house of Number 12 Grimmuald Place.
He could do this more often. He pulled out the magazine from hid back pocket and smiled. He found his new investment - a beautiful cherry motorcycle. All of the possibilities would be endless. He would even make it have the capability of flying. That would be awesome.
James would even want to ride it as well as the other Marauders - Peter not so much. Rebellious behavior is the only way he could be heard amongst his stubborn family and in all honesty it was worth every pretty penny.