From my experience, it seems that a lot of times when I scaling an object, I would want the bottom of the object stays as it is. For example, think about scaling a lamp on a desk. If I scale the lamp, I would want the lamp to stay on the desk, not going below the desk.
I know the origin decides that, so the origin needs to be at the bottom centre (that is, centre in the X and Y axes, but the lowest in the Z axis). But in the Object -> Set Origin, there is only "Origin to Centre of Mass". I have searched Google and found ways like selecting the bottom face, move the cursor there and then setting origin there, but that seems cumbersome, especially if I have to do it over and over again. Isn't there an easier way? Like "Origin to Bottom Centre of Mass" menu?