Lighting is a very broad term.  I work for a part of the industry that sells very specific products, mainly residential products. 
The interesting part of my job is that it is not all about just a style for the right look, it is more about the functionality of the fixture. I get to be creative and think technically.  I guess that part is more challenging for me to deal with.  But I like that.  Also, we have to keep up with the new lighting fixture designs. These items are introduced in the market twice a year.  The lighting technology is ever-changing also. Its these challenges that keep everyday interesting.