Having faith in the stocks of companies with strong leadership is critical to successful investing, CNBC's said on Wednesday.

But in some cases, investors give companies too much credit. For Cramer, the most glaring example was Amazon, a company the "Mad Money" host refers to as the "Death Star" for its seemingly unfaltering ability to crush any rival in its path.

For example, in 2016, a Jefferies report warned that Amazon could go after auto parts retailers like AutoZone and Advance Auto Parts. Shares of those companies plummeted as a result, spending much of 2017 in decline.

"Well, guess what? The big calamity? It never materialized," Cramer said. "We overestimated the prowess of Amazon in the auto parts space and we underestimated the power of AutoZone."

Until recently, shares of CVS exhibited a similar pattern. As the drugstore operator prepared to merge with Aetna, investors worried that Amazon's moves in the pharmaceutical and health care spaces would encroach on the deal's potential.

But after CVS' better-than-expected second-quarter earnings report, "I think we've given Amazon too much credit and CVS too little," Cramer said. "As powerful as the Death Star may be, it can't wipe out a whole industry overnight."

For more on why investors should have faith in particular companies including Disney, click here.

Smart speaker maker may have come public earlier this month to , but Cramer had some reservations after reviewing the company's business model.

With high-end wireless and voice-enabled speakers on its product list, Sonos' key selling point is its repeat business: 37 percent of its new product registrations in 2017 came from existing customers.

But as consumer technology becomes more durable, Cramer worried that Sonos' recurring business could eventually become saturated: how often will customers really need to replace their costly speaker systems?

Sonos' business, which has produced conflicting results quarter to quarter and is further complicated by its , reminded Cramer of a not-so-hot name he once backed: .

For more on why Cramer finds Sonos' stock risky, click here.

Short-sellers might be rigorous in their methods, but CEO Elon Musk hasn't made it easy to short the stock of his automaker, Cramer said Wednesday.

"There are four fundamental problems that make shorting stocks especially dangerous, problems that are bedeviling these professional pessimists as they confront perhaps the greatest short-buster in modern memory, ... Elon Musk," Cramer said.

Cramer spoke one day after of taking Tesla private on Twitter, igniting an in the stock and roughly $1.3 billion. maintained in a statement on Wednesday that no final decision has been made.

Musk's $420-a-share price target showed "why it's so tough to bet against individual companies," Cramer argued, turning to the first flaw: the notion that Musk did something wrong by opining on his company's future.

For the rest of Cramer's list, click here.

Consumer spending on health care for their pets is undoubtedly on the rise. Now, Idexx Laboratories, a leading player in the veterinary tech and diagnostics, is bringing a new type of treatment to the mix: preventative care.

"We see preventative care, including bloodwork, as one of the major long-term growth drivers," Idexx Chairman and CEO Jonathan Ayers told Cramer in a Wednesday interview.

Ayers said when veterinarians run blood work on healthy, adult dogs, there is a one-in-seven chance that they find "significant underlying disease."

"[Pets] can't tell you how they feel, and so the diagnostics is sort of the voice of the pet," Ayers told Cramer. "And what our innovation does is it expands their vocabulary so they can tell us more about their health status."

To watch Ayers' full interview, click here.

Cramer also took an interest in the performance of shares of CarMax and AutoNation, two competing car dealers with totally divergent stock paths.

Since the start of 2018, shares of CarMax have gained 17 percent, beating the S&P 500's performance, but AutoNation's stock has sunk 7 percent.

"They're both big auto dealership chains with hundreds of locations, they both sell new and used vehicles, so how the heck has the stock of CarMax been able to leave the stock of AutoNation in the dust?" Cramer wondered.

The answer boiled down to their businesses. While the two companies look similar on the surface, they are differently structured, with CarMax focusing primarily on used cars and AutoNation raking in twice as much revenue from new cars as used ones.

Therefore, as tariffs on steel and aluminum boosted prices on cars and car parts, AutoNation ate those costs while CarMax profited from selling its lower-tax used cars.

"No wonder CarMax is wiping the floor with AutoNation," the "Mad Money" host said. "The bottom line? At the beginning of the year, I told you to avoid AutoNation's stock and stick with the better-run, used-car-vehicle heavy CarMax. That's been a good call, and, if anything, things are looking even better for CarMax here, especially since its stock remains darned cheap, selling for just 15 times next year's earnings estimates."

In Cramer's lightning round, he zoomed through his take on callers' favorite stocks:

: "It does qualify as a dividend play. Now, when you get those, you remember I like . This has been a very challenged group. I like . I screwed up on that one for ActionAlerts. My problem is this: you have to understand that the group's just had a big move and it's going to cool off because did not have good numbers, so be careful."

: "No. This is a very challenged group right now. by the way, this whole sector that involves construction I'm getting a little cooler on, so I'm going to say no to that one. Sorry."

Disclosure: Cramer's charitable trust owns shares of Amazon.