You can enjoy learning Japanese. In fact, you must enjoy yourself. Otherwise, what’s the point? Why make learning Japanese an exercise in masochism for yourself? The key is to do/use things you (already) like.
A lot of the things you typically like doing may not seem (or even be) very productive. They may even be weaknesses. For example, I like reading comics, watching Hollywood movies, listening to rap music, playing video games, browsing Wikipedia articles of the most random sort, eating candy, and cetera.
It turns out that all these things and many more enjoyable activities in life use language in either spoken or written form, and they can, in principle, all be done in Japanese (with the exception of watching The Daily Show with Jon Stewart ).
If you lack certain strengths or have a lot of weaknesses, then exploit your weaknesses for the purpose of learning Japanese. If you like playing video games, watching movies or even playing sports, simply make sure you do all those things in Japanese and/or with Japanese people (I played with a soccer team made up entirely of Japanese students plus me; too bad I don’t like soccer). You could go running and play Japanese music while you do it…there’s enough stuff out there for all your tastes.
This all sounds like a game, and it is, but at its core, it’s also about responsibility. There neither time nor room here to blame classes for sucking, teachers for boring lessons or classmates for being stupid and dragging you down. Even though all that may be true, you are responsible for making sure you enjoy yourself while learning Japanese. No one else is.
There is no such thing as something being “boring but effective”. There are no “language-learning vegetables” that taste bad but that you have to eat because they’re good for you; classes have been peddling that lie for years. Of course you may need to go out of your way to learn Japanese, but if the methods you’re using bore you, then those methods need to go.
So, have fun at learning Japanese. Because having fun won’t just be fun, but it will also ensure that you choose to do it again and again (repetition). In fact, you’ll want to do Japanese so much, that you’ll need to pull yourself away from it in order to do things like take showers — and even then, you can hook up some Japanese audio to play while you wash yourself.
When learning Japanese is fun for you, you’ve practically won already, because you’ll readily choose to make it the center of your life.