Stationary bikes are the devil.
I get off work at 6, and this time of the year the sun is down by 5:30, so I don't get to ride the mountain bike, so I've been doing the stationary bike at the gym on my cardio days. I am convinced that thing is Satan. On a bicycle, you usually get some sort of break where you're coasting, either regulating speed to the terrain or going down hill, not with a stationary, you adjust everything to your preference and go till you're about to fail, at which point, you hope you can slow it down without it snapping one of your ankles, then you take 2 minutes, curse under your breath, realize you're doing this to be better than you were last year, but the stationary bike does not care how pathetic you are, it just sits there, staring into your soul, planning on snapping your ankles so as to make all the suffering in vain, staring at you with pity.