Look no further than Rory McIlroy, the No. 2 player in the world, who didn't hit a fairway after the 10th hole, shot 42 on the back nine and posted a 78, his worst score in 27 rounds at the U.S. Open.
This year's U.S. Open, though, is taking that to another level.
"It rained the day before, and there was no wind, so the course was soft", he said. That led to a double bogey, which hurt him as badly as making only one birdie. "It's still Saturday - 36 holes is a very long time in a U.S. Open".
Elsewhere, playing partners Fleetwood and Harman again matched each other by following up Thursday's 67 with a two-under 70 to reach the half-way stage atop the leaderboard.
What raises immediate questions about Erin Hills is the number of players under par, even with so many top stars struggling.
The leaderboard is about as tightly packed as it gets going into the weekend however, with 34 players within five shots of the lead. He missed the 15-footer. His 7-under par tied the record to par for the first round of a U.S. Open held by Jack Nicklaus and Tom Weiskopf, who each shot 7-under 63 at Baltusrol in 1980.
The 44 subpar rounds broke the first-round mark of 39 at Medinah in 1990. "I've got a nice run leading up to The Open", said McIlroy.
Fowler started on the back nine and sank birdies on Nos.
Casey finished his wild day with six straight pars for a 1-under 71 to set the target Friday.
"The USGA was saddened to learn that a spectator at Erin Hills passed away a short time ago", read a statement.
Willett shot a 9-over 81 in the first round and then withdrew before his tee time in the second round.
It sounds as if Erin Hills is becoming more challenging with each passing minute.
Another warm, dry day is drying out the course, and the players are noticing a difference. "So that just kind of gave me a confidence boost, knowing I can hit those shots". "And I've been very light on competitive rounds this year, and it's just a matter of getting into a good round of golf now".
Bill Haas played bogey-free in his round of 68 and joined a group at 4-under 140 that included Harris English (69) and Marc Leishman (72).
English says "They want par to be a good score, and this afternoon it will be". "I was trying to stay out of the way of Rosey". There was some good stuff mixed in with a lot of poor stuff. He just missed an eagle at the par-5 seventh after a long putt rolled just wide of the cup.
Having eagled the first hole, Casey recovered from a bogey on the tenth to card three birdies in the next eight holes. This one he'd rather forget. But then he three-putted from long range on the 13th and the 14th, and lost all hope when he missed the green on the 17th while going after the flag. Fowler tees off in the afternoon. Moments later, he began a run of five straight birdies that put him right where he wanted to be going into the weekend.
While the former took a share of the haflway lead with a 71 which owed so much to heart and perseverance, the latter submitted to the cut in a performance which is beginning to sum up his miserable season.
The birdie streak finally ended with a bogey at the sixth, where he three-putted from 96 feet at the 252-yard par-3.