One of the nicest gestures anyone can do, is to simply invite you to their home. It may seem simple enough, but dig deeper.
If it's to reminisce, have an informal meeting or just dinner together; they're literally inviting you to their happy place.
A home is supposed to be a safe/enjoyable place. So to be invited into a person’s home, is a very nice gesture.
But that doesn't mean you can mooch off your gracious host. Oh no, which is why we have today's man-law...
Man-Law #13: Don't Show Up Empty Handed
More often than not, you don't go over to someone's house without eating or drinking something eventually. So if you're doing a small get together, at least ask, if you should pick-up something on the way over. This phone call can go a long way.
Now, if you're going to someone's house for a BBQ or Thanksgiving, then you MUST bring something over (or else you may get stoned). A case of beer, a mixed veggi platter, your favorite dish to share...ANYTHING FOR THE LOVE OF GOD!!!
If people can go out of their way to invite you over, then you can at least pick up a pie at the local pizzeria!