Top definition
When your on a win streak in a game or sport and a person with the last name of Humphrey joins and you start an instant decline and lose multiple times in a row.
"hey man i was just on a huge win streak but this guy joined and now i lost 4 games in a row"

"same man fuck the Humphrey effect"
by promemerlmao December 08, 2016
Get the mug
Get a humphrey effect mug for your cat Abdul.