The only chance I’ve had at inheriting anything thus far in my 49 years is when my (childless, widowed) Great-Aunt passed. Unfortunately, she was … not a very nice person. So, she had (within her last couple of years) gotten her will changed to cut out my Dad and “all his descendants” (because, y’know, he got sick and didn’t call her nightly for an hour while he was in the hospital). She left the bulk of her estate to the local Zoo, and a particular (small) cash amount to some sort of 2nd cousin once-removed because they bore the brunt of her last 2 (of 98) years.
I figure it’s nice to get the “Be cut out of someone’s will” bucket list item checked off early. 
My Dad passed, and whatever non-debt (small, if any) he had passed to his 2nd wife. And, I’m totally fine with that because she’s still going strong 8 yrs later and likely to have another 10 or so.
My Mom has set things up so that it’s either a 50/50 split between me and my sister, or else a 3-way split between the grand-kids, depending on order of death. (I’m not sure how it goes if my sister passes but I don’t, and then there’s either an extra 1/6 lying around or else … ? I should probably read the will at some point.)
But, she did, specifically, call me to say that she planned to make my sister the executor of her will. I applauded her choice of the child who is a lawyer admitted to the bar in the state the will will be read in, rather than the child who is not a lawyer and lives in a different state. She was glad that I saw it that way, rather than feeling it was some sort of favoritism or power thing.
I can’t imagine any of my Aunts or Uncles leaving me something, simply because all of them have their own kids & grandkids to take care of.
I think, if I were named in a will with 2 cousins, I would expect there to either be an even split, or else a broadly known “well, you know little Johnny (who is actually 45 yrs old, but still gets called little Johnny by the family) was driving him to all of his doctor appointments for the last 5 years” type of thing to explain a difference.
And, I could see being disappointed if there weren’t really anything like that form of explanation.
In the case of my Great-Aunt, it was something of a relief not to need to find some sort of annual tribute that she would deem worthy of keeping me in the will.