tidsoptimist Share definition Flag Someone prone to falling into the Planning Fallacy, underestimating the time needed to complete a task because of an optimism bias. Tidsoptimist: I'm sure we can build the Sydney Opera House in 4 years!14 years laterBruh. tidsoptimist by Haomakk January 21, 2021 0 0 Get merch Get the tidsoptimist mug. Buy Now — $32.95 See more merch