The ability to engage in internal thoughts without external stimulation is a unique characteristic in humans. The current research tested the hypothesis that people metacognitively underestimate their capability to enjoy this process of "just thinking." Participants (university students; total N = 259) were asked to sit and wait in a quiet room without doing anything. Across six experiments, we consistently found that participants' predicted enjoyment and engagement for the waiting task were significantly less than what they actually experienced. This underappreciation of just thinking also led participants to proactively avoid the waiting task in favor of an alternative task (i.e., Internet news checking), despite their experiences not being statistically different. These results suggest an inherent difficulty in accurately appreciating how engaging just thinking can be, and could explain why people prefer keeping themselves busy, rather than taking a moment for reflection and imagination in our daily life. (PsycInfo Database Record (c) 2022 APA, all rights reserved).