Growing up in a country preacher's home, we often had people over for snacks and fellowship after an evening service. Invariably, Mother made popcorn. Usually we had something sweet, too-- cookies or cake or maybe pie. But always popcorn.
The nice thing about popcorn is that it is very inexpensive to make and practically everyone likes it. Mother had a battered old skillet with a lid that was the "popcorn pan." I don't think it was designed to be a popcorn pan, but I never knew of it to be used for anything else. She'd heat a little oil in it, then add the popcorn, and shake-shake-shake the skillet over the burner. If there were a lot of guests she would keep popping corn until everyone had all they wanted.
These days I use the microwave to make popcorn. But I don't use pre-packaged microwave popcorn (usually). Instead, I have a plastic microwave "popcorn popper" that uses regular popcorn. I know microwave popcorn is not terribly expensive, but this is even cheaper... besides, you can flavor it or season it the way you like! My husband likes some of the popcorn seasoning blends that are on the shelf in the grocery store right above the bags of popcorn. Me? I'd just as soon have it with melted butter (not margarine!) and plain ol' salt.
And guess what? If you come over to my house for Wednesday night Bible study, I'll serve you popcorn! Along with something sweet! I guess it's just a family tradition.