...you forget to charge the damm thing
I imagine that my Rio battery is inside, reclining on a hammock and taking things easy!
After 4 decades of being let down by failing batteries in torches, razors, cameras, walkmen etc., I'm too old a gimmer to grasp the concept of relying on rechargeable batteries, with fantastic life, and religiously move it from dock to cigar lighter plug in the car and even once an extension lead in the garden(but the battery was flat). One day, I promise myself I'll grasp the white heat of technology!