Financial luminaries offered plenty of pessimism at the Milken Institute Global Conference this week.

And here's a best hits compilation, as published by Fortune's Chris Matthews.

• Former Treasury Secretary Tim Geithner, now president of private equity titan Warburg Pincus, offered this view on where the economy is headed in coming years: "We live in a scary, dark, messy and uncertain world. That is the normal state of mankind."
• Mohamed El-Erian, chief economic adviser at Allianz, reiterated his concern that economies still aren't strong enough to thrive in the absence of support from central banks. "While the Fed is easing its foot off the accelerator a little, [other central banks] are pressing their foot even harder. So collectively, we're still in the central bank trade," he said. As a result, it's likely "we're going to have a major adjustment" in the next two years, El-Erian noted.
• Real estate legend Sam Zell addressed the issue of slowing population growth in many developed nations. "This is the worst demographic situation we've had in 500 years," he said.

Jeremy Warner, assistant editor of The Daily Telegraph, isn't too much of an optimist either.

A whopping 30 percent of government debt in the eurozone — about 2 trillion euros worth — now carries a negative yield, and that amounts to a financial crisis in the making, he says. The 5-year German government bond yields negative 0.04 percent.

"What makes today's negative interest rate environment so worrying is this: to the extent that demand is growing at all in the world economy, it seems again to be almost entirely dependent on rising levels of debt," Warner writes.

"The financial crisis was meant to have exploded the credit bubble once and for all, but there's very little sign of it. Rising public indebtedness has taken over where households and companies left off."

Global central bank easing has led to frothy financial markets, Warner explains. "The bond market bubble is just the half of it. Since most other assets are priced relative to bonds, just about everything else has been going up as well."

And what's the endgame?

"Eventually, there will be a massive correction, in which creditors will suffer sickening losses," Warner maintains. "Nobody can tell you when that moment will arrive."

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