I picked up a cheap probe thermometer to nail my milk steaming temps, but the readings kept jumping around like crazy. Turns out the probe wire was too close to the steam wand and picking up interference, took me 3 weeks and 14 ruined lattes to figure that out. Anyone else had a silly gear issue that made them question their whole routine?
That whole "question their whole routine" bit hit home. My buddy spent a month battling a scale that would randomly add 3 grams to his dose, thought he was losing his mind and redialing his entire grind. Turns out his cat kept walking across the counter and sitting on the scale pad, and the weight sensor was picking up the little furball. He only figured it out when he caught the cat in the act, mid-pounce, right before a shot. Fourteen ruined bags of beans and he wanted to strangle that cat.