“ The party is walking through the forest at night when they come upon a clearing. Half a dozen black-robed corpses lie scattered across the ground, and a pentagram of blood is shoddily drawn in the dirt.
It seems these people summoned something they could not control. Whether or not the demon returns is up to the GM, but it would be just as rich if the demon never returned, and for the rest of the night, every stray sound or odd shadow will be jumped at!”
                        
                     
                                    
                        “ These magical boots empower the wearer with several abilities at once. Wondrous leaping, water-walking, and even flying! Yet the boots possess an insidious curse upon them as well. A deep and almost unfathomable (by others) feeling of listlessness, boredom, and even apathy affects the boots' wearer at all times whenever they are donned. Magic will not dispel the effects.
And so while the wearer of the boots can perform great feats of action during combat or at other opportune times and key moments, they'll never really want to do so, complaining 'Meh, what's the point of it all anyway?' or 'I would fly up and save us all guys, but sigh, maybe uhm, soonish, mkay? Bit bored by this whole burning tower at the moment.'
Naturally the boots wearer's fellow PCs will grow quickly frustrated with this arrangement. There have been numerous occasions when one angry PC  literally tears off the boots from his companion's feet in anger, and dons them in turn, only to immediately suffer from the same effects. 
The solution lies in constantly 'motivating' the boots' wearer with successful rolls, involving threats, flattery, fiery speeches, or even bribery.”