When television commentators talk about the "hardest hole" on a golf course, they're almost always wrong. Usually, the hole they're referring to is the hardest par--or the hardest par 4--and that's not the same thing. The hardest hole is the hole with the highest stroke average, period.
My home course has just nine holes; to make a complete round you play it twice, from different tees. Our sixth hole is a par 5 the first time and a par 4 the second. Most members think of the par 4 as the harder hole, because the par 5 is easier to par, but the par 4 is actually easier, because the tee is 60 yards closer to the green. The goal in golf is not to shoot par, or even to make birdies. The goal is to take as few strokes as possible, and when you lop 60 yards off a hole you make doing that easier, not harder--exactly as you would if you bought a new driver that made you 60 yards longer off the tee.
The hardest hole is the hole with the highest stroke average, period.
Par is an arbitrary designation, not a limit. I recently played an extremely short course, whose second-longest hole was less than 200 yards. Regulars think of that hole as easy, because it's listed on the scorecard as a par 4. If it were called a par 3, they would think of it as hard--but it would be the same hole. My father and his friends reckoned par the way bond traders do, as 100. Doing that made them happier about shooting crummy scores, but it didn't turn them into better golfers. Their 98s were still 98s, even if they called them "two under."
Golfers playing an unfamiliar course will sometimes ask whether a particular hole is a par 4 or a par 5--and then play it differently, depending on the answer. But that makes no sense. If going for the green in two (or three or four) is the right choice for that golfer at that moment, it's the right choice no matter what the scorecard says par is. Playing a hole "in regulation" doesn't protect you from an opponent who plays it one stroke better, and three-putting is still three-putting even if by doing so you don't "lose" a stroke to par.
I'm an unreliable judge of golf courses, because I've never played one I didn't like, but I get annoyed when I hear a golfer dismiss a course as "not much of a test." Usually he means that when he played it he had no trouble shooting whatever he shot. But as long as you need more than 18 strokes to play 18 holes you have room for improvement. If you think a course is boringly easy because you routinely play it in the low 70s, you need to start thinking about playing it in the high 60s. You haven't used it up yet.
During this year's Open Championship, at the Old Course, the commentators and just about everyone else said the hardest hole was the 17th, the Road Hole, on which the final-round scoring average was 4.80, almost a full stroke over par. But the hardest hole, by far, was actually the 14th, on which the scoring average was 5.225, more than four-tenths of a stroke higher. Now, No. 14 is labeled a par 5 and No. 17 a par 4, but so what? If the R&A had called the Road Hole a par 5 and the 14th a par 4 (or a par 6), the results would have been the same. Jordan Spieth would still have needed to shoot 273 to get into the playoff, and Zach Johnson would still be the guy with the claret jug.
People were also wrong about the Open's easiest hole, which they invariably said was No. 5, a 570-yard par 5. Over all four rounds it averaged 4.464, a half-stroke under par, but it was actually the Open's third-hardest hole, because its stroke average was just a fraction behind the Road Hole's. The truly easiest holes (as is almost always the case) were the shortest ones--Nos. 8 and 11, the only par 3s--which averaged nearly a stroke and a half lower than No. 5. Alister MacKenzie once wrote that the 11th "may be considered one of the ideal holes of the world." Too bad it's not much of a test.