@CookiePusher got me thinking about assumptions and how they are really at the root of all wedding drama. One of my favorite sayings is "when you make an assumption you make an ASS out of U and ME" and it's so true. There are lots of them on all sides and I thought I would list a few that popped into my mind:
Bride/Groom assumptions
everyone cares about their wedding as much as they do
everyone wants to help
everyone will help, especially if it means saving money
everyone wants to celebrate - even if it means being selectively invited to things and/or tiered hosting
shower entitlement
bachelor/bachelorette party entitlement
guests covering their plate
wedding party is fine with normal/expected expenses (i.e. attire) without discussion
Guest assumptions
automatically given a +1 even if the invite doesn't specify
children invited even if the invite doesn't specify
invitations are transferrable
you can verbally invite people you think the hosts "forgot" to invite, especially if it's your family
Feel free to add! (as you can probably tell I am a list maker)