A grump will inevitably find something to get grumpy about. When at a party, and a little inebriated, and more than a little bored, an imp is likely to cause the most delightful mischief. Never go to a party with a grump. A grump is highly unlikely to dress outrageously except for Halloween. There is a fair-sized coven of imps who dress for Halloween all year round.
Imps are the ones who often appear a little distant and distracted when surrounded by grumps.
The one lone person looking for someone to talk to. Impitude is a very delicate phenomenon. When grumpitude reaches a certain level it will vanquish impitude. These are the moments when the imps have been made to look foolish and silly by the grumps. Impitude is in itself a subversive act.