It wasn’t clear who would headline the Concert for Valor when it began. Would it be Bruce Springsteen, who was inducted into the Rock and Roll Hall of Fame in 1999 and has lent his celebrity to veterans charities for years? Would it be Metallica, the heavy metal heroes whose music has resonated with this generation of American service member?

But rapper Eminem took the honors, fresh off the release of a freestyle in which he suggests he’ll punch singer Lana Del Ray “in the face twice like Ray Rice.” That already was controversial, but then Shady added fuel to the fire with his salute from the stage to those who have served.

“Happy motherf—ing Veterans Day,” he said — and then Twitter exploded.

Never mind that the foul-mouthed salute was greeted by plenty of cheers. Or that Eminem swearing is about as common as a 19-year-old lance corporal standing watch somewhere. The faux-controversy erupted anyway, and was one of the worst things about the show.

Here are some of the other best (and worst) things that happened, as seen by Checkpoint. I was standing among the crowd off of 4th and Independence streets, with a lot of veterans.

Metallica brings dozens of veterans on stage for performance
Anyone doubting whether Metallica would have its heart in the concert was quickly answered. The band came out with a thunderous performance of “For Whom the Bell Tolls,” and had dozens of veterans on stage during the performance.

The band followed with two more classics, “Master of Puppets” and “Enter Sandman.” In between, frontman James Hetfield offered this: “We finally get to play for our heroes.”

Anti-war music at a show for valor
One of the biggest surprises of the night was Dave Grohl, Zac Brown and Springsteen combining to perform Creedence Clearwater Revival’s 1969 hit, “Fortunate Son.” Written during the Vietnam War, it’s a raucous takedown of blind patriotism, class warfare and those who are quick to send troops to war without going themselves.

The song was greeted with energy by much of the crowd, as this video shot on site shows:

But the third verse in particular — in which Springsteen sings that he “ain’t no military son,” is taking heat. Some questioned whether it was the appropriate choice, as my Washington Post colleague Justin Moyer already noted. Reactions are mixed:

Springsteen’s performance got additional scrutiny because he not only played his 1984 mega-hit “Born in the U.S.A.,” but stripped it down into an bluesy, acoustic version that highlighted its dark lyrics. Decades after its release, casual fans still confuse it with being an upbeat patriotic sing-along. But it actually includes lines like “I had a brother at Khe Sanh fighting off the Viet Cong / They’re still there, he’s all gone.”

Reaction, again, was mixed:

As noted previously, Springsteen has been involved in veterans charities for years.

The Black Keys not mentioning the reason they were there

The Black Keys took the stage relatively early in the concert, playing hits “Howlin’ for You,” “Fever” and “Lonely Boy.” Notably missing, however: Not once did they give the veterans and active-duty troops present a shout-out. Wasn’t that half the point?

To be fair, though, their performance was popular:

Carrie Underwood brings out the "Singing Sergeants"

Country star Carrie Underwood’s performance turned into a sing-along for many, especially during her hit “Before He Cheats.” But it was another song of hers — “Something in the Water” — that gave the Air Force’s chorus, the Singing Sergeants, a chance to shine.

The group is based at Joint Base Anacostia-Bolling in Washington, and includes 23 musicians, Air Force officials say.

Reaction to videos of inspiring vets
In between performances, the crowd — and viewers on HBO at home — were shown videos of inspiring veterans who are profiled in the new book “For Love of Country,” by Starbucks CEO Howard Schultz and Washington Post journalist Rajiv Chandrasekaran.

Several of them, including Medal of Honor recipient Leroy Petry, were greeted with a warm ovation when it was revealed to the crowd they were in attendance. Petroy, who lost his right hand while throwing an enemy hand grenade away from two fellow soldiers, appeared to get emotional at the response.