An unusual cultural shock for me was tissue and handkerchiefs. In Japan, usually near the train stations, you can find people passing out packets of tissue.
These aren't your ordinary tissue, these are advertising tissue. Many companies use this tactic to get their name out.
Now, you might think that having one packet would be enough and you would be wrong. A lot of the toilets in the train stations do not provide toilet paper, so having a couple of these tissue packets definitely come in handy. (There are also some vending machines at the entrance to most restrooms, but I can't see myself paying 100yen (about US$1) for a little packet of tissue.)
Blowing your nose with tissue in public is also considered rude, so you will often hear the Japanese "recycling things" with their noses and throats on the trains and buses...eeew! (I think I would rather see someone blowing their nose than to hear them making these sounds.)
So, why don't they use their handkerchiefs to blow their noses? This is because their handkerchief is used to wipe their hands after washing them in the restrooms. Paper towels are rarely provided in the train station restrooms. Although nowadays, there are some train station restrooms that have those hand dryers.
Another use of handkerchiefs are as napkins. Many restaurants do not have napkins unless you go to very upscale ones, so a lot of women use their handkerchiefs for their laps and as napkins themselves.
Growing up with tissues for noses, paper towels in restrooms and napkins while eating, I thought it was kind of odd about the wiping of hands on handkerchiefs. Although, I do agree that using your handkerchief in lieu of a paper towel or napkin would be helping the environment. (Not used to this handkerchief and tissue carrying I do sometimes forget to bring a handkerchief or some tissue and end up borrowing Satoshi's...)