It could be delusions or there may be something to it.
There are a lot of unexplained occurrences still happening in the world that haven't been solved yet.
I lived in a place once and on my first night there the lights acted strange with flickering and I said "Knock it off!" and it stopped and never happened again. I've found that if you get serious with them and make it clear that you won't put up with any foolishness then, they tend to leave you alone.