Many of my family lines traveled with groups and cousins - first, second or third - ended up marrying. So keeping track of some of the collateral lines is needed to sort some of the people out. It gets complicated the way some of these families interweave over the generations.
Other collateral lines are interesting. For instance, Josiah Harlan is a distant cousin: http://en.wikipedia.org/wiki/Josiah_Harlan I knew he had to be related, so I looked up the exact line. The Harlans are easy, though - there have been books written about the family and Mom has copies. Another collateral is Sir Francis Drake - one of my ancestors was reputed to be descended from him, but Sir Francis never had children. My sister did the research and found evidence that we're descended from one of his brothers, if I remember correctly.
Another was a woman named Laodiciea "Dicey" Langston:
On another occasion, the Bloody Scouts broke into their home and threatened to kill all the Langston men. Only her father was present. He had been crippled during the war and wasn’t able to defend himself as well as he once could have. The Bloody Scouts held him at gunpoint and she stepped in front of her father, shielding him with her own body. She told them they would have to kill her first. One of the Bloody Scouts was so impressed with her bravery, that he stopped the assault and kept the others from killing Dicey or her father.
http://www.diceylangston.com/I'm descended from Dicey's father but I sort of wish I were descended from her!
I do keep track of the children of ancestors' brothers and sister, though usually I leave it at that unless there is some indication they could lead to a connection.
That is so cool about the chest in the Metropolitan! And it is so true about professions running in families. Our family lines have had doctors, engineers and farmers. My husband's family runs to artists and attorneys. The same professions show up over and over.
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