Being present after work when you're completely drained

How do you do it? Honest question. I come home after 8 hours and my tank is empty. Kids want my attention, my wife wants to talk about her day, there's dinner and baths and bedtime.

I feel like I'm going through the motions instead of actually being there. Not getting angry or anything, just... checked out. It's probably not fair to my family.

Anyone figured out how to actually be present when you're mentally exhausted?