Why are violas larger than violins? They are the same size, the violists heads are smaller.

or

An old Scotsman was sitting in a pub, nursing a wee dram, when a young man came in and sat down beside him. The Scotsman looked around him conspiratorally and spoke to the young man.

"Aye laddie," he says, nodding towards to the window, "Do ye see that stone fence oot there. I built that. Took me ages, stone by stone, month after month, year after year, But I finally did it! But do they call me McTavish the Stone Mason?......."Nooo," he says shaking his head.

Then he takes a sip of his whiskey again and after awhile he turns to the young man seated beside him and quietly points to the bar. "See that bar there laddie, I built that. Cut and planed each board lovingly I did, polished it all to a high gleam, took forever it did, but do they call me McTavish the Carpenter?.........Nooo."

Then he points out the window again and says, "And see that pier oot there laddie, I built that, piling by piling, plank by plank, through wind and raging storm, took me months, and I did it. But do they call me McTavish the Pier Builder?.......Nooo," Then he says in exasperation under his breath again to the young man, "But you f**k one sheep……………