I find Hot Corners an essential MacOS feature, especially when using apps in full-screen mode or screen sharing. One downside of the feature is that it’s easy to accidentally activate. A way to prevent this, which isn’t at all obvious, is to require a modifier key as well as moving your mouse into the corner.
When configuring a hot corner, hold down Shift ⇧, Control ⌃, Option ⌥, or Command ⌘ when choosing the function the corner activates. Each corner can be configured independently to use a different modifier key.