If not I'll live, but man, you think there's nothing between your pointer and the thing you want to select, and trolol, a cloud or mist fx just blocked your selection.

You can select your effect (or object, actor ...), and press "1" (numpad) twice. "1" once more to make it reappear (when selected), and Alt + 1 to make every hidden object reappear.

Edit : Or you open the View > Show/Hide Window, where you can hide objects by type. (Not sure there's a checkbox for FX though)