my favorite erroneous data/outlier story:

uncle was running a study on fish and had students helping note down behavioral data. everyone's collecting data, it all looks pretty consistent, all good.

ONE student is getting really bizarre outlier data though. what's going on? they observe HER observing THE FISH and realize that the fish actually ARE behaving differently when she's taking the readings.

turns out: because she's the shortest in the group, she's the only one the fish don't all immediately notice when she comes in to take readings on them in their tank. everybody else is taking readings on stressed out fish, she's taking readings on undisturbed fish.

there are a ton of important lessons. i mostly just think it's really funny how bad we are at this stuff though.