One dry sunny day Gandalf and Bilbo were returning to the Shire having completed their quest to reclaim Erebor from Smaug.

'I think it time we stopped for the night' Declared Gandalf. 'For it would not be wise to continue as the light is fading fast'.
'Suits me, I'm hungry' exclaimed Bilbo. Gandalf gave him a wistful look but proceeded to tie his horse to a tree. Trees were sparse as they had arrived at a rocky outcrop on a hill.
'Master Baggins, if you are so hungry then find some firewood before it is dark'.
Realising that Gandalf was clearly in one of his grumpy moods, Bilbo obliged quickly, relishing some solitude away from the patronising old fart and his glare of inspection.

He walked off towards the nearest trees. As he stepped, his foot caught on a rock and he stumbled down into a rocky ravine. Feeling bruised, Bilbo slowly inspected his wounds but suddenly he realised beside him an object.
'Whats this?' He puzzled.
Turning around to see clearly, it looked like a small bow with a large wooden chamber. He stepped towards it and it became clear it was a stringed instrument. Bilbo gave it a disharmonious strum causing an unpleasant sound. He now felt excited, knowing that he could cheer Gandalf up with this new found object.

'That is not nearly enough firewood' Gandalf asserted with raised eyebrows and scepticism at Bilbo's smirking return.
'This isn't firewood Mr Gandalf, I found it in the rocks, Look' Bilbo said handing the instrument to Gandalf.
'Ahh, yes… hmm… I see'. Gandalf inspected the instrument and turned it in his old hands. With his long fingers he gave it cacophonous strum.
'Good heavens'. Gandalf began to twist the little knobs at the neck of the instrument to bring it in tune. After patiently waiting for a quite a while, Bilbo interjected, 'what is it Gandalf?'.
Gandalf looked up with irritation, 'this' he began, 'is a guitar'. 'Be warned, it is unlike other stringed instruments, It holds within it a kind of power. I have no evidence, but I have a theory that Sauron forged these instruments to snare middle earth with popular songs of a quality that, it would get stuck in your head and drive you to the limits of sanity. Few are practised in its ways thankfully.' Gandalf paused thoughtfully. ' I once knew a beggar in Minas Tirith who played just such an instrument and begged for money. Come to think of it, I'm quite sure Radagast the Brown played a guitar'.

Having finished fiddling with the guitar, Gandalf gave it melodious strum. 'Ah there we are'.
Bilbo exclaimed ' marvellous Gandalf!'. This evening had become fun for Bilbo, as hobbits loved the jovialness of music, just as they enjoy the pleasures of food and growing things. With a gasp Gandalf realised it had become dark and frustratedly set off to get firewood, igniting his staff to light the way. As Gandalf disappeared, Bilbo saw the guitar sitting where Gandalf had left it. Picking it up carefully, Bilbo plucked some stings…

Half an hour later Gandalf returned. To his amusement and disdain Bilbo was fluent in at least four chords and singing merrily. He sang and strummed and danced around.

'Soon will be the day when I'm rid of the foolishness of hobbits' Gandalf murmured as he began constructing the fire. After 10 minutes of tediously listening to Bilbo sing and be merry Gandalf broke. 'Have you considered where that guitar came from?' Gandalf said condescendingly. 'What if its owner comes to find it being lessened by your impertinent tongue? You do know such things in the wild are usually an omen? Its previous owner could be dead but you wouldn't care'. Bilbo stopped playing and looked at Gandalf. 'Gandalf I've been meaning to say, I found a curious ring in the misty mountains, I think it might be…' 'Don't change the subject, that guitar is clearly a danger to you and possibly the fate of middle earth' Gandalf exclaimed (interrupting Bilbo). 'Cast it into the Fire' Gandalf urged. There was a pause as Bilbo weighed up his love for the guitar versus his fear of Gandalf's scary mode. 'Destroy it!' said Gandalf angrily now standing up with fists clenched. Then in a moment Gandalf snatched the guitar and threw it onto the fire. Bilbo cried. 'Stupid Hobbit' Gandalf said self-righteously. Gandalf smugly sat back down, stretching his arms and legs, and feeling that all is right in the world.

The rest of the night was awkward, but Bilbo forgave Gandalf after a few days for his insensitivity. Gandalf however, try as he might could not get Bilbo's songs out of his head, for days it tormented him as they journeyed towards the Shire. At times Bilbo would start humming it and suddenly stop when he realised Gandalf was listening. Like an insect in his head it was slowly driving him crazy. Only months hence did Gandalf shake the frustratingly catchy tunes from his head, thus preventing him from thinking carefully about the imperilled state of middle earth or the other curious object that Bilbo found. All Gandalf thought about was how he might 'destroy the lost guitars lest the enemy recruits them to his purposes'.