I had some pieces I couldn't string together. I got the local Assizes records and in there there was the father's name. Trouble was, looking at the Census etc one'd assume it to be the chap who lived closer (1 mile away/same village, instead of 2 miles away/in town).... I realised that I had the right one by pinning the information I had against just one of them. Without the "pieces" I'd have just assumed the other chap "must be right as he's just up the road and has the right name".
Further pieces and tying him into the specific family I'd got for him then came out in a court case published in the newspapers that made me triply sure I absolutely had the right man/family ... trouble was, "the dead end trail" also ended at the same point. "Went to Canada..." and that's where I'm still stuck, except I DO now know he is the right chap, so could at least draw the tree back a further 4-6 generations even if I have no idea what happened to him.