In a 5-year longitudinal study of young community adults, the authors examined subjective temporal perspective (STP) "trajectories" derived from ratings of past, present, and anticipated future life satisfaction (LS) collected at two time points. Upward STP trajectories (past < present < future LS) were normative at both time points. Opposing hypotheses were derived from the literature concerning the potential positive versus negative implications of upward STP trajectories. Using latent trajectory modeling, individual differences in STP trajectories were examined in relation to mental, physical, and interpersonal functioning as well as future satisfaction bias (over- vs. underestimation of future LS). Steeper upward STP trajectories were associated with less positive functioning, both concurrently and prospectively, as well as greater future satisfaction bias. Therefore, rather than representing a realistic, adaptive form of self-enhancement, steep upward STP trajectories for LS appeared to be a form of fantasizing and wishful thinking, associated with distress, dissatisfaction, and dysfunction.