I'm with Starfish...obsessing on the grade is relaxing. When I first got my Garmin, I really played with the grade. Not so much for my climbing, but I was starting to put together what people were talking about in bike races. I had grades that matched (although, around here, they're rather shorter in distance).

Now, at home I play grade for the fun of it. I keep track of max grade and feet climbed per mile of a route. I can tell you where my local steepest hill is at 21% and that my training hill is around 8%.

On vacation, it is more fun. Although you cannot use the instantaneous grade read out when you're riding (e.g., that spike to 30% was just an anomoly), like Starfish said, it helps. The GPS will tell me if I'm climbing a false flat, but, more important is the mapping to a "oh, this is an easy hill"-hill.

I had the GPS on my Italy trip and it was relatively new. It was the first time I'd rode somewhere with sustained climbs. The leader laughed at me (ok, with me) as the hill perception changed throughout the trip. First it was, "Hey, I can recover on a 4% grade!" and by the end of the trip it was "Oh, blessed 9%. I'm so glad to see you and say goodbye to 12%".

Oh, yeah, I obsess. No question.