It kept nagging at me. Why was the "hot corner" in Debian's version of GNOME 3 so "sensitive," compared to the GNOME 3 desktop's hot corner in Fedora 19?
In Fedora, I'd mouse into the upper left "hot corner," and half the time wouldn't get the app panel or search box to open. I'd have to "aggressively" mouse to get it working.
So I've been using GNOME 3 less and less. Was it just too slow?
Today I did a bit of searching and found out that "hot corner" sensitivity was something that the user can set, not in stock GNOME 3 but with the Activities Configurator extension.
I installed the extension and cranked the sensitivity number way down, from 100 to 43, making it more sensitive. Now my "hot corner" is much more responsive to mouse movement, and GNOME 3 is easier to use.
Once you have the extension installed, you can access its settings via the GNOME Tweak Tool, or by right-clicking on the "Activities" menu or the little smiley face that now appears to its left.