The best parts of seeing lots and lots and lots and lots of bands in just a couple of days are the surprises. I was surprised at how miserable the park got and how crowded it was, and how dirty it was, and how many people were stubborn enough to sit around in those stupid folding chairs right in the middle of a mass of rock fans all day long so they could be within 150 feet of the Flaming Lips. But let’s just conclude that I’m not the target market for these kind of events and move on, shall we?

I’d heard about David Yow’s antics, but seeing them Friday night was still a pleasant shock. Even without revealing his testicles, Yow put more bile and blood into his performance than anyone all weekend. As soon as the Jesus Lizard struck their first chord, he ran full-out down-stage, leapt off the edge, over the photo pit, headfirst into the waiting arms of a legion of shouting fans. He spent most of the first three songs (“Puss,” “Seasick” and “Mouthbreather,” chosen by online voters) stage-diving. As his hour of growling neared its end, you’d have been forgiven for assuming that the 48 years-old Yow would be getting a little tired, but during “Blockbuster,” he took some time out for jumping jacks and push-ups. The band’s jagged riffs have aged almost as well, and with the loudest crowd of the weekend assisting, the Jesus Lizard set a very high bar early on.

The Mae Shi surprised me and the thousand or so people who showed up in time to hear what turned out to be their last ever show, or maybe the first festival appearance of Signals. Whoever it was, they brought on some local guests to rap and shout and sing, and they gave their all to showing everyone a really good time. Mission accomplished.

On the smaller B-stage, Sunday afternoon provided the one-two punch of the Japandroids and the Vivian Girls, two small groups (a duo and a trio) who proved even more impressive on stage than they are on record. Japandroids stuck to the loud-fast-rules formula as they ripped through a drums ’n’ guitar set that had everyone in the vicinity cheering and the kids in front looking completely enraptured. The ’Droids’ lanky Brian King made it difficult for anyone to seem radiant by comparison, but the Vivian Girls did so anyway. Sloppy and super lo-fi on record, the Girls were a drum-tight and sometimes thundering live unit in person. They clearly took a lot of pleasure in playing for the appreciative crowd, who were amply rewarded by a band willing to push themselves right to the edge of ripping out of control.

Plants & Animals were also surprisingly good live, much more intense than their record indicates. Pharoahe Monch demonstrated everything that can be good about a live hip-hop show, while Doom’s lazy set confirmed everything bad about one. Frightened Rabbit used pure passion to conquer the afternoon glare; Yeasayer proved that their clubby world music works just as well in the bright sun; and Beirut proved there are some indie music fans who actually go absolutely ape shit for horns. The Thermals and Fucked Up also deserve credit from bringing energy and enthusiasm as large as the crowds. And every time I see the Walkmen, I’m reminded of how damn good they are. I listened to all of their albums on the way home.

Every year Pitchfork assembles a group of bands on the edge of major success and gives them a chance to show up some more experienced indie stars. In this context—a crowded park, the often-blazing sun, audiences that migrate if you can’t keep their attention—only true heroes of live music make their mark. Even perfectly competent and sometimes inspired live bands like the National and Grizzly Bear look a bit stale after a day of watching hungrier acts leave it all on the stage. Built to Spill, whose tunes fruitfully expand to suit the occasion, felt dull after seeing the Jesus Lizard try to tear the place apart. Of the “vets” (a comparative term, in some cases) only the Flaming Lips, bringing to bear every trick in their spectacular repertoire and attacking rarities and oldies with gusto, managed to seem like they really wanted it. And that’s what the weekend was all about, writ so large, it’s easy to see which bands have it, which ones never will, and which ones are determined enough to work for it.