In the RC hobby, we have used lithium batteries since they were first available. Learned long ago to treat them gently. Always charged in a fire save container, don't overcharge, don't charge at high rates. Have seen many explode or catch fire. We have seen a number of planes catch fire in the air as the lithium batteries either overheat or explode. Carrying one in you pocket is just like carrying a live bomb. Quality batteries, used properly are a great source of power, light, small and high capacity. Used improperly, or low quality, can be disaster.