In case more evidence was needed that we live in disconcerting times, Z100's Jingle Ball, which usually serves as the summary for the year in pop music, was extraordinarily dark Friday night at Madison Square Garden.

The Weeknd ended the five-hour extravaganza with "The Hills," his icy, chart-topping R&B dirge about hiding his true personality through excessive drug use. Um, happy holidays?

Of course, some of that is to be expected with The Weeknd as the headliner, whose set was a stunner. After all, as chipper as his Michael Jackson-esque hit "Can't Feel My Face" sounds, the lyrics betray a dangerous mismatched relationship built on numbness and the admission of "I know she'll be the death of me."

However, the dark side of pop appeared so often throughout the show, which will air in edited form nationally on the CW Network at 8 p.m. Thursday, it may as well have been the night's theme.

The buoyant Aussie rockers 5 Seconds of Summer took a break from their punk-flavored pop to deliver a snarling "Jet Black Heart." Caribbean hitmakers R. City explained how the catchy smash "Locked Away" was about their father's time in jail. Pop singer Charlie Puth explained how his wistful song about the late actor Paul Walker, "See You Again," changed his life.

"I just got three Grammy nominations for it," said Puth, who struggled a bit with his falsetto throughout his set. "One year ago, I was in my house in New Jersey. One year later, I'm playing for thousands and thousands of you."

Fetty Wap delivered his summer hit "Trap Queen," about a couple teaming up to sell drugs, from a gold throne after he broke his leg in a motorcycle accident.

Luckily, there were thunderous DJ sets from Zedd -- who opened with "Beautiful Now," his collaboration with Lake Grove native Jon Bellion, and played "Clarity," which he co-wrote with Seaford native Matthew Koma -- and Calvin Harris to lighten the mood, as well as nicely choreographed sets from Fifth Harmony and Selena Gomez.

Heartthrobs Shawn Mendes and Nick Jonas got the mostly female crowd screaming with their sets. However, it was Jonas' older brother Joe, who unveiled his new band DNCE, who offered the biggest surprise with fun, escapist dance pop like "Cake by the Ocean" and "Toothbrush."

And leave it to Demi Lovato to capture this moment of collective uncertainty perfectly with her set that moved from esteem-building to pain -- with the show-stopping "Stone Cold" that she belted out powerfully and emotionally -- and then back again.

Lovato confessed that when she writes songs now, "I want it to help somebody get through a rough time." Her set certainly accomplished that at this year's Jingle Ball.