There's a funny skit on the May 18 episode of Saturday Night Live called "Romano Tours" about a tour guide who wants to remind you that taking a vacation in Italy is not going to change you personally (see below). I think it does reflect the belief many people have that a vacation "might be just the thing" to spice up a relationship or get the family closer. It usually doesn't work.
But psychologist B.F. Skinner supports changing your environment to change your feelings. So why don't vacations changer your emotions? I'm going to guess he'd say that while you're changing your surroundings, you're probably not changing the reinforcers and punishers that are currently shaping your behavior. If you and your mate/family have a maladaptive way of interacting and you still use that way of interacting on vacation (which you probably will), then a change in scenery isn't going to have any positive effect.
Any other thoughts on why this video seems to really nail what we experience during or after a vacation?