What we don’t all know

Pet peeve, and a very serious one: People introducing concepts in sacrament meeting addresses with something like “We all know that…”

No, we don’t all know about whatever—many of us may, but what about non-Mormons who may be visiting, or people who have been away from the church for a while, or small children, or even people you’d expect to know but happen to have missed that concept somehow? I mean, i suppose you could get away with it in a very small group where you know everyone really well, but even there it’s a risky claim.