For me, I see moving guys like any other person in the service industry (haircuts, waitress, etc.), thus feel that a tip is earned for a job well done. Like other service industry folks, they work hard for what really is low pay if you think about the back-breaking work they do. In my mind a tip says thank you for doing something I can't do myself, I appreciate you doing it and appreciate the attentiveness and care you've given my property.
I do think, after having lived on the east coast and now in the midwest, that the thinking on tipping varies by region of the country.....since moving here (midwest) we've continued to tip as we've always done while living in NY/DC/NJ/CT and a lot of folks are surprised to get a tip.....like the furniture delivery guys who delivered my sofa and two bedroom sets a couple of weeks ago - said they usually don't get tips, but certainly appreciate them! It wasn't a big tip in my mind - $10 for each of the two delivery guys - but they took good care of bringing things into the house, set up everything for me, moved some things around - all totaled, spent about an hour in my home.....in my view they went above and beyond what was expected, thus earned a financial thank you from me.....$20 total for an hour of good service from guys being paid just $8 an hour to deliver furniture. Ya know what? When they deliver the rest of my order on Friday this week, I KNOW they're going to do a great job again!