See Fitts'* law [1]. Buttons at the corners you describe can be modelled as having infinite width, making them much easier to aim for.
Fitts, Paul M. (June 1954). "The information capacity of the human motor system in controlling the amplitude of movement". Journal of Experimental Psychology. 47 (6): 381–391. doi:10.1037/h0055392. PMID 13174710.
* * * This shit dates from the nineteen-fucking-fifties. * * *
And people fuck it up all the time.
This is why we cannot have nice things.
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Notes:
1. I will be that guy and note you misspelled it. I've done that plenty myself.
In general, opinion seems to be divided as to whether the possessive form of a singular noun ending in 's' takes an apostrophe 's' or just an apostrophe: https://en.wikipedia.org/wiki/Apostrophe#Singular_nouns_endi...
That'd make a great tombstone.
This is one thing that pisses me off about stuff switching to web apps. We had this stuff mostly figured out in the 80s and early 90s, but now web developers are all re-inventing it, often from scratch, or using different or conflicting standards. Now menus close when you mis-point by one pixel, the tab key in forms only sometimes works, drop-downs look different on every single webpage. All the UI work and knowledge of the 70s, 80s, and 90s out the window. Sigh.