Throughout middle school and high school, my friend was completely obsessed with Maple Story. He would stay up until 4 or 5 AM and then sleep for an hour before school. Then he would use up time trying to find the best DPS or gear to have but would somehow still be passing class. When he finally kicked the habit he calculated how many hours he used of his life and it came out to over 2 years I believe (17,531+ hours within an 8 year time, just to put it into a worse perspective).