I've seen this said on here numerous times-- the style of the invitations lets the guests know the formality of the event. This is often said to posters who want to tell guests what to wear (which I would never do, by the way). But I want to make sure I'm not choosing invites that don't match the formality and leave my guests feeling uncomfortable. For every wedding invitation I've received, I've never "assessed the formality" based on the invites. So can you all give me examples of what would make an invitation formal vs. more casual?