I once took a plate of these to a baby shower and they were gone in sixty seconds. Then I took them to a work drinks thing and same thing happened. They are so simple, but so yummy, and don't shy away from using butter and avo on the same sandwich. Remember, it's a sandwich, not the Caboolture line.
Ingredients

Ripe avocado, mashed
Basil dip (see this pic for the one I use, I get it from Woolies)
Butter (I use Lurpak, who doesn't?)
Fresh white bread (yes, white)
Method
If you haven't made a sandwich since 1989, here's what you do.
Get two slices of bread, spread lightly with butter, spread one slice with mashed avocado and the other slice with the dip.
Put some chicken on one slice, not too much, you want the ingredients to share equal billing. There's no star here.
Join the slices together, and cut into three fingers. Not sure why, but three fingers is the best way to eat these. You can cut the crusts off if you a) wish or b) are younger than eight.
Repeat until you're either tired of making sandwiches or you think you've got enough.
Eat immediately.