They constantly flush wet wipes and bottle caps down the toilet and it clogs up the pumps and pipes.
Also washing their feet/shoes in the sink before using the toilet.
This is my experience in the men's washroom I don't know what the female one is like.
Canada BC specifically
The proper use of flushing toilets and bathroom etiquette
The industry I work in has many new Canadians and I believe they all need a crash course on this from the companies they are working for.