Transportation network companies (TNCs) have introduced shared-ride versions of their ordinary services, such as UberPool or Lyft Line. The concept is simple: passengers pay less in fares for an incremental increase in time spent picking up and dropping off other riders. This paper focuses on the social and behavioral considerations of shared rides, which have not been explored as thoroughly as time and cost trade-offs in transportation. A survey of TNC users conducted through Mechanical Turk in June and July of 2016, which had 997 respondents across the United States, found that ( a) users of dynamic ridesharing services reported that social interactions were relevant to mode choice, although not as much as traditional factors such as time and cost; ( b) overall, the possibility of having a negative social interaction was more of a deterrent to use of dynamic ridesharing than the potential of having a positive social interaction was an incentive; ( c) there was evidence that a substantial number of riders harbored feelings of prejudice toward passengers of different social class and race, and these passengers were much more likely to prefer having more information about potential future passengers; ( d) most dynamic ridesharing users were motivated by ease and speed, compared with walking and public transportation; and ( e) safety in dynamic ridesharing was an important issue, especially for women, many of whom reported feeling unsafe and preferred to be matched with passengers of the same sex.