Oh, I used to HATE dressage. I thought it was worse than watching grass grow or paint dry.. yucky.
But then I got into the cool stuff, like being able to control each step Dancer took, and well - that is just too cool. Being able to do multiple lead changes, canter sidepass... it was all just really really neat.
The beginning will be well.. boring. It's tedious, but keep at it, it gets really really cool after the boring beginning stuff, and it will totally benefit your jumping. I guarantee it.
All the Grand Prix showjumpers are dressage horses first and foremost; they can all do upper level dressage as well as showjumping - just something to think about :)