Goblins

"Clap! Snap! the black crack! Grip, grab! Pinch, nab! And down down to Goblin-town You go, my lad! Clash, crash! Crush, smash! Hammer and tongs! Knocker and gongs! Pound, pound, far underground! Ho, ho! my lad! Swish, smack! Whip crack! Batter and beat! Yammer and bleat! Work, work! Nor dare to shirk, While Goblins quaff, and Goblins laugh, Round and round far underground Below, my lad!”

— J.R.R.Tolkien

Goblins are trickster Spirits, mostly harmless nuisances that can still be quite bothersome in the wrong place. They are not very dangerous but it is still unwise to anger them.

Creation: It is unclear from what souls goblins are created, speculations include notorious pranksters, sharlatans and scammers. Goblins dont keep track of such silly things when there is fun to be had.

Notorious Nuisances: Goblins love pulling pranks, annoying people, being an inconvenience and just generally bothering those around them, It is their signature trait for which they are famous.
They do it mostly for their own amusement and to get a reaction, but while they might not mean any harm that does not mean that they do not inadvertently cause such. They are also not nice creatures, they have almost no patience or compassion and will pull their mean pranks on kings and beggars equally.
They are generally regarded as pests among other spirits and among those capable of magic, though to ordinary people they are major impediments to their daily life whenever they appear and dangerous if angered.
Luckily goblins possess very short attention spans which greatly limits what they can actually do, so they don't have the patience to pull elaborate schemes and pursue long-winded plans of revenge if somebody disturbs their latest 'game'.

Mortals: Goblins love mortals, at least those that either get angry at their pranks or those that join in with their games. They will do whatever they can come up with to get a reaction, they will throw horse manure at passers by, compose terrible poetry, steal coins and jewels and hide them and open animal coops so the farmers have to find and capture them again.
They might also pull more subtle pranks by sneaking about in the shadows and misplacing items, just to then laugh as the silly mortals have to spend hours to find their lost objects. Goblins can be very sneaky if they want to be.
Those mortals that deny them their reactions or are just not 'fun' the goblins leave alone, and they will flee from those that present an actual threat to them.