It is never easy to get up early before work or waiting till after work to squeeze in a few hours of training time. Especially if your working on movements or techniques that are not "the fun part" of kung fu i.e. stances or whatever. Knowing that the key to perfecting a technique only comes from doing the same thing over and over and over and over.....(I get tired sometimes just thinking about some exercises) This is usually a point where martial arts practitioners can have a "mid life crisis in their style" and seek new intrests outside of what they are studying.
There is nothing wrong with dabbling in other styles but the unfortunate truth is learning a little bit of everything will hinder you from ever mastering a style. Or another way to say it is not being rooted in any style asures that you are easier to knock down.
Dont worry there is no such thing as an ultimate style. Every martial arts that has survived till now has endured the test of time which means it has been proven effective. The only catch is that you have to train all of the flaws out of your system and practice against all possible scenerios with your style.
So how do you stay excited about the same movements? The answer is change your training. There are an endless amount of ways to train that will not only prepare you for more situations but at the same time add luster to your own style. For example for kick training I used to design my own regiment to make sure I could kick fast and accurately by testing the limits in different terrains, in the ocean for balance, on gravel to learn to use rocks to my advantage, wet grass or in the forest. Then practice kicking against other styles, grapplers, capoeria stylist, wing chuners, etc. Aside from sparring you can use tools to keep you motivated such as candle training, underwater training, extreme weather training etc. Your training techniques are only limited to your imagination. Try new ideas to stimulate both your technique and motivation.
The point is Martial Arts is a HARD LONG road.....you gotta find a way to keep it new. Or eventually you will become one of those guys who says, I used to do a little karate."