Get a group of guys together, and it's not uncommon for someone to dust off a rousing, "Listen to this stupid thing my wife did or said," story. You know, the kind about how your wife can't add, or buys the stupidest thing, or spends too long with her makeup in the morning, or is confounded by the simplest appliances. My undercover sources tell me that at all-female gatherings, the equal and opposite happens, with hilarious anecdotes about husbands inability to cook, lack of hygiene, social gracelessness, emotional cluelessness, obsession with sports, mechanics, hunting, etc.
Whether drawn for humor or simple camaraderie (after all, most people beyond a certain age have a spouse, so in a given gathering there should be at least that one level of commonality for most people) spouse put-downs are cheap and easy conversation.
The problem is, getting into the habit of complaint is dangerous. It's easy for us all to find things about our spouses we could wish otherwise, but when we complain about them with others, we implicitly distance from the spouse while drawing close to others. More importantly, once you start to complain about something, you notice it more. Complaining frequently about your wife's spending habits or your husband's tendency to leave his dirty socks scattered around the room makes you notice it more, and makes the repetition more annoying.
"There she goes again! Sheesh. Wait till I tell people about this one."
What seems like a way of making small talk can actually become a way of identifying things about your spouse which will come to annoy you more and more. Feigned annoyance for social purposes can turn into a real grievance, making what seems like harmless socializing dangerous.