Do you not feel the urge to always be online when you're working from home? Once I clock out I can't keep myself from checking emails/slack etc.
It can get to be a serious problem, but my solution is to just close the stuff while I'm working, and set time aside to check it when I get up to refill my beverage and relieve myself. If somebody really needs to reach me, then they can call my phone.
Update: In addition to that, for the moment I have the luxury of doing exactly what I want, and selecting who will employ me for it, so that could be affecting this considerably. I think the holy grail would be learning to convince myself to enjoy my work even if some day it's untangling some ridiculous JSP cobweb instead of porting compilers.
But generally just tune out from work and make sure you are disconnected.