What I love most about Japan are the cherry blossom trees. They are so beautiful! I really want to go to Japan during the Spring time because that is when the cherry blossom trees are in full bloom and also when they look their best.
It's the appreciation for fine craftsmanship that first drew me to Japanese culture. Whether it is in dyeing, papermaking, toolmaking, woodworking, there is a love for finely wrought items that thrills me.
I agree with lilithcat about the crafts artists, but they are a special case of the general attitude that everyone takes pride in doing their job as well as they can.
And I have to add the onsen (hot springs) and public baths.