Engagement photos are a great way for a couple to get to know their photographer. They can get a feel for how the photos will be on their wedding day and I get a chance to figure out how best to interact with them from behind the lens.
Most engagement photos have a very posed look that can come across very stilted if the couple isn't into it. Since I tend to work in a very candid style, it's an easy problem to overcome. Couples like Greg and Cathy turn to each other for strength when things get weird, and having engagement photos taken is most definitely weird. It's easy to photograph intimate, loving moments at times like that. I would just pose them let them do their thing for a while. By the time we finished there were smiles all around and batch of beautiful photos.
I think when you make it a point to have fun, it comes across in the photos. It's hard to go wrong with a couple of genuine folks in a beautiful location marking a milestone in their life together.