Jamba Juice is one thing because it isn't on every street corner, whereas buying Starbucks cards for people you know spend money on coffee every morning is not a bad investment. Furthermore, with Starbucks' cards, it allows you to start redeeming points for more drinks and gives you incentive to keep re-upping the value to earn those points. I get a free drink/food item every two weeks from what started as a gift card that turned into a gold card. Do I have a consumption problem? Sure. But it was a benefit to my already-shitty lifestyle and I can't complain.
I find they're actually quite good gifts for smaller or more casual situations - as a thank you for someone who did you a favor, or when you don't know someone all that well. Or even for people who just like coffee.
Maybe they're normal, and you're insane. Data sure supports that idea :)