Woody Allen’s most recent film, Midnight in Paris is a perfect story.

Not the romance stuff so much. All that’s OK. As always, the Woody Allen character (played by Owen Wilson) is found irresistible by young and beautiful women. Ho hum. Right. It’s his movie, he can do whatever he wants with that.

But the way Allen handled the premise of longing for the past dazzled me. Yes, of course. That’s exactly how it is.

Nostalgia is seductive. We yearn and yearn for bygone days, when life was simpler, or more creative, or more exciting, or more…whatever. Whatever we need at the moment.

Are those good old days really that much better, or is it just easier to imagine they are because we can “remember” only what we choose to?

One type of yearning for the good old days is called historical nostalgia. Tourism researchers are interested in historical nostalgia. So are marketers. They’ve figured out that it’s a good way to sell stuff to people. They’ve also figured out that music is particularly powerful for stirring up nostalgic feelings, which is why the soundtrack of every other TV commercial these days is classic rock. Come, boomers, spend your money here. It will bring you back to the days when you had hair.

Nostalgia is a powerful sales tool. Psychologically speaking, however, it’s long been frowned on.

The word itself has negative connotations. First recorded in 1920, “nostalgia” was coined by Swiss doctor Johannes Hofer and combines the Greek words nostos (roughly, yearning for home) and algos (suffering).

But modern-day researchers find that nostalgia is actually pretty useful.

“I see nostalgia as the glue that keeps things together,” says Krystine Batcho, a psychologist who studies nostalgia. “It maintains continuity of self, helps you remember who you are despite the fact that so much happens to an individual through a lifetime.”

Nostalgia can help us feel more firmly anchored to our own identity. So that’s who I was, that’s how I got here from there, that’s how I’ve changed and that’s how I’m the same.

Even remembering hard times can have positive results. “When you reminisce about bad times, part of the good is that you know you’ve survived, overcome and defeated them,” Batcho said.

And people often grow nostalgic when they are coping with change or hard times. “Nostalgia appears to help social bonding,” Batcho says. “People who are more personally nostalgic tend to be more pro-social in terms of their coping strategies in times of stress.”

This seems to relate to a recent article in the Journal of Personality and Social Psychology that calls nostalgia “an existential resource.” In other words, it helps us feel that life has meaning.

Among the six studies described in the article was one in which the researchers used an essay to induce an existential crisis in participants.

There are approximately 7 billion people living on this planet. the essay read in part. So take a moment to ponder the following question: In the grand scheme of things, how significant are you?

Bummer.

The researchers found people who read this essay questioning the meaning of life were more nostalgic afterwards than people who read an essay about computers.

That seems to indicate that nostalgia can be soothing. Conversely, it also appeared to buffer people from feeling too crummy about the downer essay if they wallowed in a little nostalgia before reading it.

Nostalgia can make you feel better about life. Which is cool.

But in that case, can it be like any other drug and subject to abuse? Could too much of it become a substitute for finding meaning in life in the present?

I’ve been feeling very nostalgic recently and the pleasure of it has been wearing thin. Which leads me to believe there’s something more to be learned from nostalgia. Too much nostalgia and you might have to start asking yourself “What is it, exactly, that I miss most? And how can I find it in the present?”

While you’re thinking about that, go see Midnight in Paris.