"The plug had fell down the back of the cupboard and he assumed the blender's plug was the toaster's"
We get through life with our brain applying continual learned assumptions for what appears to be a similar context.
It is only when the conscious part of the brain takes over that we analyse exactly what we are seeing/hearing. Even then it often wrong because it is what we "think" we are seeing/hearing - rather than what is actually there.
The golden rule of trouble-shooting.
"Don't believe what anyone else says they have seen. Only believe half of what you think you have seen yourself"