The stock of Allergan seems to be on a one-way path of struggle and endless competition, CNBC's Jim Cramer said on Thursday. "It can't catch a break," the "Mad Money" host told a caller in the lightning round. "Sage Therapeutics has got a competitive drug to something that they may be doing for depression. The other day we saw another company, Revance [Therapeutics], have a competitive product to Botox. Doesn't matter that the CEO, Brent Saunders, just bought a lot of stock. Nothing matters. This stock is a one-way stock." Cramer even compared Allergan's stock to bitcoin, the wildly popular digital currency that also seems to be on a "one-way" path to $20,000 and possibly beyond. "It is the anti-bitcoin," Cramer said.

Don't let the sellers spook you

Marc Benioff Frank Muldoon | CNBC

It's easy to call the market "crazy" or "irrational" in the face of an unexpected sell-off like the one that happened in the technology stocks this week, Cramer said on Thursday. "But the market's not crazy, nor is it irrational," he said. "In reality, traders tend to make wild over-generalizations. They act fast, they paint with too broad a brush and it's a mistake to assume that they really know what they're doing. In short, the market's often wrong." Even as tech stocks recovered later in the week, Cramer wanted to point out some of the most puzzling names that were thrown away by hasty sellers. Cramer began with the stock of Salesforce.com, a massive cloud company with its hands in nearly every part of customer relations and enterprise software.

Cramer's 5 bitcoin suspicions

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With the CBOE, CME and Nasdaq hopping aboard the bitcoin train to offer their own derivatives of the wildly popular cryptocurrency, Cramer issued a warning about the craze. "After its recent ascent, bitcoin's become some sort of abstruse casino game that seems to have only winners and no losers. You've got to like that, right? I think, though, that could change," Cramer said. "Whenever any security runs from $5,000 to $10,000 to $15,000 to $19,000 in a matter of weeks or even hours, you've gotta wonder how long it will be before it bursts." Given the buzz around bitcoin, Cramer said that it could still have room to run even after Thursday's rally, which brought the digital currency above $19,000 for the first time. But the "Mad Money" host still came up with five reasons to be suspicious of the trend.

Boeing CEO on tax reform

Jim Cramer speaks with Boeing CEO Dennis Muilenburg at the NYSE on Dec. 7th, 2017. Dillon Rebock | CNBC

As the House and Senate move closer to passing tax reform, Boeing Chairman, President and CEO Dennis Muilenburg told CNBC that he sees the effort as critical to economic growth. "I think tax reform is the single most important thing we can do in this country to unleash economic energy. It's going to unleash growth," Muilenburg told Cramer in an exclusive interview on Thursday. Corporate tax cuts would be particularly good for Boeing, which had a 23 percent effective tax rate in 2016, according to the non-profit Institute on Taxation and Economic Policy. Muilenburg said that the global aircraft manufacturer would put the additional cash to work mainly by boosting its $6-billion-a-year research and development budget.

Boeing CEO on growth, space travel

Dennis Muilenburg, CEO of Boeing. Dillon Rebock | CNBC