White tile floors arent hard for me to clean. In fact, I think they are easier, because you can SEE the dirt. Hardwood floors and some laminates are, for me, the hardest to clean. Hardwood especially, because you have to remove any spills, and wood floor cleaners dont get them up well. I use Meyers Clean Day all purpose for this, and sometimes have to use a plastic knife to gentle scrape up something spilled (such as a carmel candy). After I get the spills or whatever up, THEN I use hardwood cleaner. It takes longer because of hacving to mop with the wood grain.
Tile floors that have a ridged surface (the ones that look like wood) can be tricky.
Old linoleum floors are a pain, too. I read somewhere the best cleaner for them is something like Scrubbing Bubbles. I havent tried that yet, but it makes sense.
Terrazzo floors are also difficult, because they are OLD, and if they are a dark color, you cant see where the worst dirty spots are.