Ironic process theory
Ironic process theory, ironic rebound, or the white bear problem refers to the psychological process whereby deliberate attempts to suppress certain thoughts make them more likely to surface. An example is how when someone is actively trying not to think of a white bear they may actually be more likely to imagine one.

"Try to pose for yourself this task: not to think of a polar bear, and you will see that the cursed thing will come to mind every minute."
— Fyodor Dostoevsky, Winter Notes on Summer Impressions, 1863
The phenomenon was identified through thought suppression studies in experimental psychology. Social psychologist Daniel Wegner first studied ironic process theory in a laboratory setting in 1987.