People regularly interact with new acquaintances, yet little research has examined the hedonic dynamics of these conversations or the extent to which people are aware of them. Five preregistered laboratory experiments (N = 1,093 participants, including 966 spoken conversations) address these gaps. We find that people misunderstand the hedonic trajectory of conversation: After enjoying the initial minutes of conversation with a new acquaintance, participants expected their enjoyment to decline as their conversations continued, but experienced stable or increasing enjoyment in reality. This miscalibration arose at least partly because participants underestimated how much they would have to discuss. Thus, instructing participants to mentally simulate the conversation in detail drew their attention to the conversation material they could discuss and helped to calibrate their enjoyment predictions. When left uncorrected, misunderstanding the hedonic trajectory of conversation can undermine well-being. In one study, participants preferred to spend less time in conversation and more time alone than was optimal for their enjoyment-a finding that emerged even among participants who reported wanting to enjoy themselves. Throughout our experiments we assessed various conversational contexts (including whether participants had one long conversation with a single partner or several short conversations with different partners), and features of conversation (including participants' perceived and actual interest in talking to each other, fatigue, and the intimacy of conversation), thus shining novel light on conversational dynamics more broadly. People hold incorrect assumptions about how social interaction changes over time and, consequently, may avoid longer-lasting conversations that would forge closer connections. (PsycInfo Database Record (c) 2022 APA, all rights reserved).