Fellow lister Pat Huck wrote me earlier today with a cautionary note, one that is worth passing on to the list I think. It emphasizes something we all face in our headlong rush to "find the goods". Without careful examination and an open mind, one can easily be lead astray and even down the wrong path. I can hardly imagine a greater waste of time.
Pat wrote:
My [advice] is not to take everything you read as "fact" without backing it up with other proof. In my 14 years of research, I have encountered many mistakes in census, Catholic Church records and in the newspaper. The census names spelled like the census taker thought they should be spelled, and not as they were correct. On my Great Grandfather, he is listed as an adult in 1860 census. His widowed sister is 1st, then her father-in-law, and then her brother, and then her 2 children. But if you didn't know, it looks like they are her brother's children. In Catholic Church records (regarding the woman who was to become his wife) she is listed with the last name ending in BERG when it should have been BENN. If I didn't know the date of her birth and the first names of the parents, I would have missed it. Now in the newspaper when my grandfather died, he was listed in a small news article as having had 2 children when he had 8 children. Good luck, Pat Huck
Yesterday Carol Payne and I had this exchange part and parcel with her Rahenkamp family dilemma:
CP: However, where the 1860 U.S. census did not show "relationships", it's probably safe to assume that the additional 3 year old boy born in New Jersey and listed in the household, was their son.
Jb: Generally speaking that would be a safe assumption until something comes along to disprove it. The percentages are greatly in your favor in any case.
While what was written is no doubt true on a percentage wide basis, one ought to be careful assuming ANYTHING, or letting wishful (or desperate <g>) thinking cloud better judgment, or overshadow the data as it is found and constituted (however incomplete it may be). The census returns in particular can be troubling in this regard, but as we all know, it doesn't end there.
Sadly some things may remain nebulous or undetermined no matter how hard we try, and until better supported, should probably remain that way. The ultimate goal for family historians is to fill in as many of the blanks as possible, but with as much hard evidence as can be mustered, as opposed to conjecture or colorful assumptions. Some of the things Pat cited in her comments make for a nice case in point. It goes without saying that whenever something doesn't appear quite right, question it and start digging further!
Mona Houser offered what I thought was a particularly sage thought not long back that is also apropos here ::
It really is difficult, at this distance of 150 years, to assign motives to the actions that were taken that long ago.
This same "distance" often makes for less than perfect and incomplete findings to boot. It highlights the struggle we constantly face in our respective genealogical quests in making sure that we don't allow wishful or extraneous notions to prevail over the evidence at hand, however scarce it may be. Many a tail chase has been the result of someone making one too many assumptions along the way.
If anyone has any additional examples or comments to offer, feel free to add them (for educational purposes, if nothing else). 
Bests to all. Jb