1; Neighbor's 5 year old son painted my entire Honda CB750F dull housepaint brown. Took my neighbor many many hours to clean the paint off. I was still finding bits of brown paint hidden away in the crevices of that bike years later. Later when I spotted the little brat abusing my cat for the second time, I corrected his behavior myself in a most direct fashion by doing exactly what I said I would do, throwing him over the fence into his mother's compost heap--kid suddenly became my best buddy because, I guess, I was the only adult around him who would set a limit and follow though with the consequences.
2. Friend "borrowed" his girlfriend's brother's Norton for a joyride. Ran wide around a corner and hit a car dead center headon. Killed him and the three people in the car. I assume the bike's owner was upset but with all that grief consuming everyone, I never found out.