Back from vacation only a short time and already feeling like you never left?

That’s not unusual, says a tourism researcher from the Netherlands who has studied the post-vacation psyche and found that the happy, mellow feeling time off can bring lasts about two weeks.

Unfortunately, most of us return to our usual routine when vacation is over, and that cuts short any afterglow, Jeroen Nawijn, of the NHTV Breda University of Applied Sciences, tells msnbc.com.

And while the quantity of time you had away doesn’t affect how long you’ll feel good when your holiday is over, your level of enjoyment of it does.

"If you had a great vacation, you experience two weeks of afterglow," Nawijn says. "Everyone else returns to their pre-trip levels of happiness right away, but they don't feel worse."

Not surprisingly, how you feel about your life and the people in it also impact the length of your post-vacation bliss, other researchers say, as does whether you’re generally a pessimist or optimist. Optimists are more likely to hang on to good feelings longer.

To read the complete msnbc.com story, Go Here.