A new study finds that the more Facebook 'friends' you have, the more likely you are to feel stressed out by the social networking site.
Researchers at Edinburgh Napier University have found a significant minority of users suffered "considerable Facebook-related anxiety".
However, they only received very modest rewards.
More than one in 10 said Facebook made them feel anxious and more than three in 10 said they felt guilty about rejecting friend requests.
The study found that 12 percent of the students questioned said they disliked receiving friend requests, while almost two thirds (63 percent) said they delayed replying to friend requests.
"The results threw up a number of paradoxes," the BBC quoted the university's Dr Kathy Charles, who led the study, as saying.
"For instance, although there is great pressure to be on Facebook there is also considerable ambivalence amongst users about its benefits.
"And we found it was actually those with the most contacts, those who had invested the most time in the site, who were the ones most likely to be stressed," Charles added.
Dr Charles said this could be because of the pressure users feel to come up with updates about their life for a large number of people.
She said: "It's like being a mini news channel about yourself. The more people you have the more you feel there is an audience there.
"You are almost a mini celebrity and the bigger the audience the more pressure you feel to produce something about yourself," she added.