I'll go on Bill V's team and concur with wetlands. Ach.
Not only because I am occassionally wild, but also for the rest of the hacks with less than perfect swings; it goes in hand with Bob Jones' quote that the water hazard is so final. It is disheartening to hit shots that might be a little bit off, and be absolutely f**ked with the result if the ball ends up in such wetlands. Not to mention what this does to pace of play on public courses.
I just wonder sometimes, were there not other ways to route the golf course around wetlands, or use grading to direct water down to wetlands on the periphery? Flynn did this with great success at Lehigh CC--note the stairsteps directing water down the hill away from #1, around #17 green, and down to the right of #2 tees. This was probably done with success at other classic courses as well.
To continue the bitch session, design of courses with the 'links-style' nine and forested nine. With the exception of Beechtree, but just because the first nine reminds me in part of Bethpage Red.
#13 at BSP-Red, by the way, is a tough tee shot, specifically because the right side and short of the bunker is SO open, and the proper tee shot must be aimed over the left-side bunkers.
Interrupted fairway? Not at all bad. Tillinghast did this with great success several times. Ridgewood, in particular, stands out, as its fairways interrupted by dolomite mounds provide a good test of shot placement and decisionmaking should one miss the fairway.