In the dog days of summer, selloffs come at lightning speed, Jim Cramer warned his Mad Money viewers Monday. That's why investors need to sell into strength and be ready to buy on the dips. Last week's selloff was typical for August and September, Cramer said, but it's by no means over.

What's got Cramer spooked about the markets? He said that Congress is not in session, for one. When they return, look for more rancor and worry to creep back into stocks. Next, Cramer said that technology might be rolling over, with weak outlooks from Seagate (STX) and fears about Micron Technology (MU) .

Third, Cramer said while interest rates are edging higher, they're not moving enough to help the banks and no rally is sustainable without the banks.

Finally, there are a number of key retail earnings this week from the likes of Home Depot (HD) , along with Walmart (WMT) and Target (TGT) . Weak earnings from any of these could derail a rally.

That's not to say there isn't a lot to like in the market. Cramer said we still have low inflation, a weak dollar and largely strong earnings across the board. But in the summer, when trading volumes are light, even that might not be enough to stem a quick selloff when you least expect it.

On Real Money, Cramer explains why dip buying works. Get his insights with a free trial subscription to Real Money.

Take That With a Grain of Salt

"Listen to yourself, not others," Cramer reminded viewers. When you see big money managers on TV, remember that they don't have the same investment goals as you do.

Cramer said he got angry when he listened to Howard Marks, founder of Oaktree Capital, offer his dire warnings for stocks last Thursday. Marks said that stocks were dangerous and investors were unaware of the risks. Those comments had an impact on the markets, he said, and ushered in Thursday's big selloff.

The problem is that Marks made the same comments back in May 2010, saying that the risks were too high and investors were oblivious to the coming decline. When he made those comments, the Dow Jones Industrial Average was at 10,868. Today's close was 21,993.

Had investors listened to Marks in 2010, they'd have missed one of the greatest market moves in history. Had they listened to him last week, they'd have missed the rally today.

To be fair, Cramer said that Marks is indeed correct about increased market risk. But as a billionaire, you need to be risk adverse. For the average investor, however, risk is part of the game. "You only need to get rich once," Cramer reminded viewers, which is why billionaires don't have the same priorities as you do.

Cruisin' Along

It hasn't always been easy to own the cruise stocks, but right now, it's never been better. That was Cramer's assessment after the remarkable runs in Royal Caribbean Cruises Ltd.  (RCL) , Carnival Corp.  (CCL) and Norwegian Cruise Line Holdings Inc.  (NCLH) .

Cramer said after crude oil cratered in 2014, it should have been smooth sailing for the cruise lines, but that was tempered by a scare related to the Ebola virus that worried passengers and investors alike. The industry quickly bounced back, however, and 2014 and 2015 were stellar years for the cruise stocks. In 2016 though, the Zika virus was making headlines and once again depressed the group, even though those fears were overblown.

More recently however, Cramer said the analysts just got it wrong, expecting other areas of travel and leisure to benefit more from Trump's tax cuts and infrastructure plans. When those plans stalled, so too did the rest of travel… except for the cruise stocks, which just kept on sailing.

Cramer noted that the group sells at 13 to 15 times earnings, less than the S&P 500 overall at 18 times earnings. And that's using the current estimates, which are likely too low. With so many secular trends pulling in their favor, Cramer said the cruise stocks are still the place to be.

Alliance Data Systems 

What should investors make of private label credit card issuer Alliance Data Systems (ADS) after Credit Suisse issued a scathing report on the company? Cramer dove in to find out.

Alliance Data has been an incredible stock, rising from just $25 a share in 2009 to a high of $300 in 2015. Those gains were short-lived however, as shares fell to just $175 be February 2016. ADS was dealt a one-two punch this year when the company missed earnings in late July, then received the Credit Suisse warning about credit quality and a risky balance sheet.

Cramer said that he's willing to give ADS the benefit of the doubt, as none of the issues raised in the report were new and the company has been able to deliver strong results for years despite Amazon (AMZN) disrupting many portions of retail. So far, the naysayers, including Credit Suisse, have been wrong, Cramer concluded, so he's willing to use the stock's current weakness as a buying opportunity.

Cramer and the AAP team are updating their bullpen -- the stocks they are following for new opportunities during the second half of the year, including 3M (MMM) , AT&T (T) and Visa (V) . Find out what they're telling their investment club members now and get in on the conversation with a free trial subscription to Action Alerts PLUS.

Lightning Round

In the Lightning Round, Cramer was bullish on EPR Properties (EPR) , Activision Blizzard (ATVI) , AbbVie (ABBV) , ON Semiconductor (ON) and Check Point Software (CHKP) .

Cramer was bearish on Sunoco (SUN) .

Off the Tape: iPic Entertainment

In his "Off The Tape" segment, Cramer sat down with Hamid Hashemi, president and CEO of the privately-held iPic Entertainment, a company working to reinvent the movie experience.

Hashemi explained that iPic is a lot more than just a movie theater. It turns an ordinary experience into an extraordinary one, which is why guests spend, on average, 4.5 hours at their facilities. The iPic theaters include dining, bars and luxury seating. 

Unlike a traditional movie theater, which derives 60% of sales from the box office, iPic only derives 30% from ticket sales. That makes his company less beholden to summer blockbusters and more of a year-round profit center.

Hashemi said that iPic currently has 16 locations with five more under construction and another 16 planned.

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At the time of publication, Cramer's Action Alerts PLUS had a position in ATVI.

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