1. A weak yen
Since the yen is having a downturn these days, it makes travelling to Japan cheaper (unless you live in the Euro area who are also facing problems of their own). The yen is expected to climb up so you better make use of this discount ASAP!
The degree of safety felt by a traveler in an area is paramount. Violent crime is unheard of. Counterfeit currency is also not much of a problem. I have left my shopping bags twice in Japan, and all of my purchases were still in tact, even after several minutes of leaving them behind. You are more likely to lose your belongings through carelessness rather than theft.
Japan is a very diverse country. It has everything for everyone. If you are a shopper, you have (to name a few) the whole of Osaka, and Ginza. If you are a nature lover, Nagano and Arashiyama are there to fill your lust for the earth. If you are a foodie, Tokyo has the most number of Michelin-starred restaurants in the world. If you are a museum and history junkie, Kyoto preserves Japanese history so well that it is one gigantic museum by itself.
4. Unique culture
Culture is one of the defining areas which determine the “interestingness factor” of a place. Japan, I tell you has a very unique culture (especially if you tread places like Akihabara).
5. Amazing people
Even with a bunch of Japanese signs, Japanese boarding calls, and the like, I have never been lost in Japan. This is thanks to the people who are willing to help. Whenever I asked people for help, they went out of their way, opened Google Maps, and accompanied me to the place that I would be going. Awesome.