Can I get a side of humor with my tragedy?

I just saw "Revolutionary Road" and it's a gem of a film; I can't think of a more brutally honest story of I've seen in some time. The two main characters, Frank and April Wheeler, are arrogant dreamers, using their fantasies to get through the day-to-day grind of reality. This is an all too familiar tactic that often ends tragically if not acted upon and fixed; I myself have used delusions of grandeur to get through a shift at one of the many meaningless job titles I've held over the years. It's America's answer to the heart-wrenching "Scenes From a Marriage" by Ingmar Bergman, though Sam Mendes, the brilliant director, shows a slightly different side of a marriage. 

Every step Frank and April take is an attempt to cover up a theoretical mistake. Their current existence is predicated on mishaps, which is realistic of so many marriages. How many people have you known that have gotten married because whatever birth contraception they were using didn't work? Oops, on with life. Leonardo DiCaprio and Kate Winslet do an exceptional job of conveying hopeless fear, something that is often "acted" onscreen instead of being genuinely felt. DiCaprio especially, who has been unfairly overshadowed by the brilliant Kate Winslet, was terrifying to watch. Something in his eyes made the audience feel the search for purpose and the revelation of fear. What does life mean? Apparently they can't figure it out.

But enough about the brilliant film; one could read a review like this anywhere and care less about it, I know I always do. Now to address the purpose of the title. Now I know most moviegoers are exactly this: someone who has a day job, a family, reads "People" and came to see this film because they wanted to see Kate and Leo reunite onscreen. These people are also often not theatergoers, which this film gives a bow to; Mendes is also a theater director. The emotions onscreen are raw, humbling, recognizable and often times terrifying; something most moviegoers aren't used to. And here's the problem: they occasionally laugh. Obviously there's a difference between a real laugh at bad acting or a funny situation but when this audience laughed they did so at odd times and I wondered why. This wasn't the first time. Once in a great while when a film comes around and tries to project something realistic I often find the audience chuckling, nervously. This isn't something they would laugh at in the confines of their own homes because it's really not funny, it's usually the opposite of funny. But why then? A friend of mine, Andrew, and I have often discussed this factor of a "regular" audience. They are confronted with such realism that they become claustrophobic of which emotions to express. Now you can shout "film elitist" at me but I'm not laughing, why would I? Embarrassment is the only thing I feel for the audience. How can you laugh at such appalling things? Has our society really come to that? We sit in a dark theater still self-conscience of how we react to certain things. I can only say to the audience, Grow up and I hope to never view "Scenes From a Marriage" with you in a dark theater, you'll think it's a laughing riot.