The question of how to leave work at work is always a tough one. I used to think that I was really good at doing this, too. Come to find out it was greatly a product of my job at the time and how smoothly it was going. As rough waters came, it was harder and harder to leave work at work.
The first thing to do is get rid of the notion it isn’t personal, it’s business. If you have chosen a position and spend 40 plus hours a week there, it is personal. Work, outside of sleeping, likely takes the number one spot on your calendar from that stand point of time.
Second, ask what it is about your work that envelopes you to the point where you can’t get it out of your head. If you love your job and love to share that with others, do it. Your friends and family can hear your excitement and it probably excites them a little. Now, this can get a little annoying, so be careful. If you can’t keep work from bleeding into your personal life and you are typically talking negative about your job, get a new job. Believe me, I know that is easier said than done.
The older I get, the more I realize how much your 9 to 5 affects your life. Don’t fight it. Take it as a road sign of where you need to go next.