I've seen studies stating that this is the case, that Facebook incurs negative social effects instead of positive, and absolutely agree. Perhaps though, now in the wake of regulators investigating a recent Facebook-sponsored and conducted study entitled "Experimental evidence of massive-scale emotional contagion through social networks", reported this month in Wired Magazine, we can take comfort of a sort in the fact that it appears to be no coincidence at all that emotions evoked by their evolving interface are distorted and uncomfortable:

The journal that published the controversial study in which Facebook manipulated the emotions of users by altering content in users’ News Feeds, Proceedings of the National Academy of Sciences (PNAS), has published an Editorial Expression of Concern regarding the study and "that the collection of the data by Facebook may have involved practices that were not fully consistent with the principles of obtaining informed consent and allowing participants to opt out.” The issuing of the statement follows regulators both in the US and the UK saying that they will investigate the matter further.

The study in question was entitled "Experimental evidence of massive-scale emotional contagion through social networks" and involved manipulating feeds to have more negative or positive content in order to see how it effected user's posts. The authors write in the paper abstract: "We show, via a massive experiment on Facebook, that emotional states can be transferred to others via emotional contagion, leading people to experience the same emotions without their awareness."

I doubt very highly that this is the first such study Facebook has funded, judging by the extensive amount of fine tuning the social environment there has creepily sustained over time. It's always felt like an ever slippier slope of engineered manipulation to me, and I do happen to prefer my reality distortion-free, especially where the power of massive corporations with nearly unlimited funds and loyalties only to profit-seeking shareholders are concerned.

But that's just my opinion; I could be wrong.