Elon Musk went to war — then made up — with Apple. Here's what happened.

Hi, I'm Matt Turner, the editor in chief of business at Insider. Welcome back to Insider Weekly, a roundup of some of our top stories.

On the agenda today:

• Employees are using a controversial tactic to force their bosses to give them a raise.
• Streetlights are turning purple — and it could be a sign of the chaos to come.
• Meet 30 real-estate professionals who are shaping the industry's future.
• Former Noom employees say they were unprepared to handle users' depression, disordered eating, and trauma.

But first: Jordan Parker Erb, the author of Insider's 10 Things in Tech newsletter, is taking us behind the scenes of Elon Musk's feud with Apple.

• P.S. 10 Things in Tech is a fun and engrossing read, bringing you the most fascinating stories about Big Tech and innovations each weekday. Sign up here to get the newsletter.

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Elon Musk goes to war — then makes up — with Apple

This week, Elon Musk, the world's richest man and new Twitter owner, declared "war" with the world's biggest tech company: Apple.

At the heart of the issue was Apple's 30% App Store fee, our associate editor Jordan Parker Erb writes. Musk isn't the first to enter this fight — developers, tech CEOs, and regulatory bodies have long decried Apple's "monopolistic" grip — but he may be the most mainstream figure to do so. Even so, history says he'll probably lose.

Here's what went down:

• The declaration of war was made in true Musk fashion — by tweeting a since deleted meme.
• Musk also tweeted that Apple was threatening to remove Twitter from its App Store — but things changed quickly.
• Two days later, Musk said the "misunderstanding" about Apple pulling Twitter had been resolved, ostensibly after the two took a walk through Apple's headquarters together.
• It's not the first time Musk has beefed with Apple CEO Tim Cook. Here's a timeline of their feuds.

Sign up for 10 Things in Tech to get stories like these right in your inbox.

Now, on to this week's top reads.

'Everybody's a free agent'

More and more job candidates are applying for new roles with no intention of jumping ship, according to recruiters. They're just looking to land an offer that they can use to force their employer to give them a raise.

Employers hate that people are using job offers as bargaining chips. If you weren't serious, hiring managers are complaining, you shouldn't have wasted their time. And the bosses scrambling to put together counteroffers are grumbling, "Where's the loyalty?" But employees are responding: "Loyalty isn't free."

How employees are winning big raises.

Why are the streetlights turning purple?

You may have seen it for yourself. From California to Wisconsin to Florida, there have been reports of hundreds of thousands of streetlights spontaneously turning purple.

There has been no shortage of wild theories for why. But no, it isn't ghost- or football-related. Nor is it some grand conspiracy. Instead, the mystery of the purple lights is more mundane and worrisome than anyone has ever realized.

Read more on 'The Great Purpling.'

See Insider's list of real-estate rising stars

Insider's third-annual slate of emerging talent in commercial and residential real estate is in.

Amid Zoomtown booms and the warehouse-construction frenzy, we sorted through more than 100 nominations to identify the top 30 professionals in real estate who are 35 and under.

See the full list here.

Inside Noom's promise of psychology-driven weight loss

The promise of the popular app Noom for psychology-driven weight loss attracted users who appeared to be suffering from depression, eating disorders, and other acute mental-health conditions, according to interviews with more than 30 people, including former coaches and former employees.

Some users understood Noom's "psychology-based" offerings to be something like therapy.

But Noom's coaches lacked the qualifications, preparation, and training to be psychological counselors and often found themselves working with clients who exhibited complex and sometimes frightening behaviors.

Read the full story.

Also read:

• Buzzy startups failed to fix mental-health care. Now their mistakes are fueling the space's next generation.
• Medly set out to disrupt the pharmacy industry. Instead, it burned through money and laid off more than half its staff as its business crumbled, leaving patients in the dark.

This week's quote:

"I wrote a memoir for one executive two months ago. He served in the French military and it was like writing an adventure story."

• Billy McIntyre, a ghostwriter who makes about $14,000 a month on Fiverr and works just five hours a day. Read how he does it.

More of this week's top reads:

• As Disney insiders fret over Bob Iger's impending changes, these are the six execs he'll trust to drive his new strategy.
• China's Xi Jinping is facing the biggest crisis of his time in power.
• Who earns more per hour: a Goldman junior banker or a Starbucks manager?
• Secret memo reveals Bush rewriting the history of the 9/11 attacks.
• NBCUniversal layoffs are coming in January. Here's what to know.
• Andreessen Horowitz's buzzy tech publication, Future, is shutting down.
• "I worked from the beach in Mexico for a week without telling my boss."
• Some Amazon advertisers are fuming after a Black Friday glitch cost them up to hundreds of thousands of dollars.

Another newsletter for you: 10 Things on Wall Street is our weekday look at the biggest stories in finance and beyond. Sign up here to keep up with all the happenings on Wall Street.

Curated by Matt Turner. Edited by Jordan Parker Erb, Hallam Bullock, and Lisa Ryan. Sign up for more Insider newsletters here.