First, the cars are relatable as the stock cars come from models that people use every day (though heavily modified). 

Secondly, the interaction and dynamics of the car and the drivers are intriguing when they are inches close to each other on the track. 

Thirdly, particularly for Americans, it is due to its local nature. A lot of the teams and drivers are native to areas and states. Meaning there's a certain element of patriotism that comes into play when picking someone to support. These result in the popularity of NASCAR both in the tangible and experiential aspects. Let me elaborate. 

As per an excellent article from Rookie Road, NASCAR is a fast-paced sport involving stock cars throughout the US. Over 40 cars zoom around a track within inches of each other and seconds separate winners from others. This is an apt description that combines all the aspects of why it is so popular. One might ask, “what is a stock car and how it plays into NASCAR?” Every NASCAR car has a few stock parts—hence the name stock car—but these are strictly cosmetic.

A stock part is a part that is made in an assembly line by the manufacturer. The only stock parts are the hood, roof, trunk lid, and front grill. The rest of the car is custom-made. What makes NASCAR stock cars relatable is that they range from commonplace brands like Toyota, Ford, and Chevrolet. Even the everyday life Camry has been modified for NASCAR. So, there is a sense of relatability in NASCAR. 

The next aspect is how close and psychologically thrilling the races are. This becomes more obvious seeing two drivers, inches from each other trying to win a fight for supremacy. It is almost like combat sports except the two cars are inches away from each other parallelly. This is quintessentially the primary difference between Formula 1 and NASCAR. It makes the latter much more exciting in my view. 

As for team spirit, those who are privy know every team has its own stars and a huge following. Jimmy Johnson for example is a superstar for those out of North Carolina and Hendrick Motorsports supporters. 

One reason for me to love NASCAR is a neighbor of mine is a racer. He used to take his regular car on the track and is an amazing driver. He is several years younger than I am. That said, he grew up to be a pro-racer. He also met his biggest rival and competitor in my local track. Once he was disqualified from a race being alleged of having extra components by the rival I spoke of. What he then did was, stripped his car’s body including the doors, and put paper over there. He wanted to prove a point. His bonnet was a flimsy cloth covering. He did everything he could to make the car as light as humanly possible. Watching this kind of dedication towards modding a car for winning a race and proving a point mostly attracts me to NASCAR.

So, there you have it. These are primarily why NASCAR is so popular and a unique sport for Americans.