The 18th is a pretty tough hole. If you hit driver the lake is easily in play on the right, and several large bunkers impinge on the left, making the landing area pretty narrow. A couple of the bunkers also have a pretty tall lip, so sometimes it is hard to hit it high enough but still have enough club to get to the green. The green is somewhat narrow but long front-to-back, and has no bailout area on the right (all water), and anything left will roll down a hill into rough or into brush (if there aren't spectators standing there). Making it a little more challenging is that it is almost always into moderate breeze coming in from the ocean; the 18th and clubhouse are located down alongside the lagoon in a valley directly open to the ocean, which funnels the onshore breeze right into your face off the tee.
If you challenge the tee shot and the wind and try to hit it long up the gap, you're rewarded with a fairly short iron into the green, but the wind will grab any errant shot and push it towards the water or bunkers Any safer tee shot leaves you with a mid iron in, which for the ladies was probably a 6 or a 5, again dealing with the wind along with a narrow-ish green. The 18th is clearly the toughest hole on the course, and I've seen many people (including me) come to the tee with a pretty good round going and then finish with a double bogey or worse.