Do you get nervous watching the groom during wedding speeches?
While he anticipates which awful, embarrassing stories are about to be recounted in front of his parents, some of the audience will likely feel their own collars tighten, mouths filling with saliva, palms getting increasingly damp.
Thanks to science, we now know why this is.
According to research at Saint Louis University, in America, we now have reason to believe that stress can be as contagious as the common cold!
And it doesn't just happen between relatives and friends - we can catch secondhand stress from complete strangers.
The university's study team set up a series of stressful situations - such as a man defending himself against false accusations, or someone subjected to an impromptu arithmetic test in public - and measured the cortisol levels in both the person under pressure and their audience.
The results were very interesting.
By and large, the cortisol levels spiked in both the person on the spot and the people watching it happen.
Even more intriguingly, the results did not seem to be affected by gender.
In other words, men and women were both as likely as each other to develop signs of sympathy stress.
Although the results of the research showed that even complete strangers were capable of "catching" stress from each other, the study also revealed that you are FOUR times more likely to develop second hand stress from someone that you know.
This has pretty big implications for our home, work and school lives.
If you spend your days, for example, surrounded by feverishly busy colleagues, tearing their hair out to meet deadlines and generally suffering the effects of not enough sleep, the likelihood is that you will soon start to exhibit some of the same symptoms, even if your day isn't quite as frantic.
This news comes at the same times as Professor John Ashton, President of the Faculty of Public Health, has come out saying that Britain should switch to a four-day working week, in order to help combat the country's high stress levels.
According to Ashton, adjusting our working week to four days instead of five - allowing people to get catch up on sleep and spend more time with their families - would help to reduce all sorts of medical conditions, such as high blood-pressure, heart attacks and depression.
This news could be even more worrying for parents.
The University of California carried out a similar experiment, in which mothers were placed in a separate room from their children and then given an overly critical evaluation, to ignite their stress symptoms.
The study found that when the mothers were reuinited with their children, the babies developed significant signs of stress too and some even displayed extra signs of discomfort around the evaluators who had participated in the critique.
The Saint Louis University team concluded from their study that stress could be passed on through facial expressions, voice frequency, touch and even odour.
So, does this mean we have to be extra cautious about who we could infect when we feel like we're coming down with a bad case of stress, as we would with the flu or a cold?
Or should we be teaching ourselves - and our children - better coping mechanisms, to avoid being the victims of secondhand stress?
Food for thought...