Given the advent of genetically modified organisms and the direct influence Monsanto has had on industry lobby groups, the laughter produced in the above grocery store comic is probably closer to nervous laughter.
Controversial jokes allow us to 'soften up' an issue and later talk about it. Once we've been exposed to a concept, it makes it easier to "think" about it, and once you get people thinking about something, words soon follow. In this respect, jokes have social influence.
Other 'out there' concepts often times dressed up in jokes are the conspiracy or intriguing mystery theories. Whether Elvis is alive, whether the ancestors of the isolated Dogon people of Mali in West Africa really did have contact with aliens, or whether or not the CIA is an unstoppable, sinister, almost supernaturally powerful organization whose Alpha's are behind every significant world event in history since the late 1940s is unknown.
Without concrete evidence that the CIA black ops division undertakes dangerous and usually what would be considered illegal missions that are not officially sanctioned by the US administration so that the administration, which usually benefits from such missions, can safely dissavow any knowledge of them in the event their publicly uncovered success or failure. The administration is in the position of plausible deniability towards the CIA's actions.
Jerry: Why do I always have this feeling that everybody's doing something better than me on Saturday afternoons?
Elaine: This is what people do.
Jerry: No they don't. They're out on some big picnic. They're cooking burgers, making out on blankets. They're not in some mall in Jersey watching their friends try to find the world's cheapest air conditioner.
In the above dialogue, we recognize a social condition whereby people forget that they 'put on faces' for others and that others 'put on faces for them'. Still, it is plausible that others really are enjoying their weekends, in which case, it is possible that they are indeed having more fun than Jerry did looking for an air conditioner with his friends, and afterwards, their car, which was lost somewhere in the parking lot. The plausibility of a other people enjoying a picnic while they roamed the parking lot looking for their car is the same plausibility that allows our minds to ask "What if?"