One unsettling reality I have had to come to terms with is that genealogical research is largely based on luck. You can write all the blog posts of encouragement and persistence you want, but it really comes done to plain old luck. Either your ancestors left records or they didn't. There are myriad reasons why that happened or not.
I am not a fan of luck, mostly because I seem to only receive the bad variety. If you are a bridge player, as I am, then you know that although contract bridge is fun, it still is about the luck of the cards dealt to you. However duplicate bridge takes the luck out of the equation and the game then solely rests on skill. Too bad we can't take luck out of the equation in genealogy.
And my ancestry is actually much luckier than most. African-Americans get stopped by slavery. Jewish-Americans, if they can back to Europe, find many documents were already destroyed during the Shoah. To know that there were records that no longer exist is perhaps the most frustrating thing in genealogy. Wouldn't we all like to see the 1841 and 1851 censuses for Ireland. It's not yet even 100 years since they were destroyed (1916).
During my hop through the town level vital records in Moultonborough, Ossipee, New Durham, Rochester, and Holderness, N.H. I was amazed that one year would have rich and recorded records and the next year would be blank. It was completely and utterly arbitrary. I was very lucky that I had ancestors die in New Durham in 1851 and 1855, but the ones who died in 1866 and 1868 got skunked (as did I).
That being said, here's my short list of records which I wish I could bring back:
1. Barnstable County (Mass.) Deeds 1685-1775ish. Originally part of Plymouth Colony (where some deeds prior to 1685 can be found), all the deeds were destroyed by fire in 1827. The people alive then reproduced many deeds that happened within their life times and the collection does stretch back to the 1770s, but hardly completely.
2. Cumberland Co. (Maine) Probate. Same thing--destroyed by fire. They only commence in 1908. 1760-1908 are gone.
5. The censuses for Ireland.
6. The U.S. census of 1890.
What are your wishes?