It’s Friendly Local Game Store. I generally just say LGS because I find the “friendly” part... I guess kind of patronizing? Like, let me be the judge of how friendly the store is. I’m luckily enough to have several game stores in my area, most of which do have very friendly staff and regulars. The one that I’ve found to be unfriendly I no longer frequent. But, yeah, while most LGSes are pretty friendly in my experience, not all are, so it doesn’t make sense to me to make friendliness a part of the acronym by default.