power - Best practice to switch +V or GND connection?

Consider LAMP1 and LAMP2 in the simple example circuit below:

Which is the "better" practice, using the switching component (here RLY1) to break the +V connection to a component that's always connected to GND, like LAMP2; or use it to break the GND connection to a component that's always connected to +V, like LAMP1?

I understand that from a purely theoretical perspective it makes no difference… But my "practical intuition" insists that LAMP2 is a better practice, because it's always grounded; thus you cannot inadvertently energize the circuit with an accidental short to ground. And yet, it seems like many (if not all) example circuits I look at connect things like LAMP1. So probably that means my intuition is wrong.

Answer

In practice it is best to switch the hot terminal, +V in your case. Ground is often connected to safety ground and as such has same potential as the world around you. When you unscrew a light bulb from its fitting, you don't want to accidentally get zapped when you touch the metals.

BTW it it also good practice to connect null to the outer terminal of the light bulb because of exactly the same reason: it is easier to accidentally touch.

With electronic circuits on the other hand, often the low side is switched with a transistor. This is in part because old logic parts were much easier made to be able to sink more current to GND than they could source current from Vcc. This is in turn caused by the fact that it used to be easier to manufacture NPN transistors and N-channel MOSFETs. Today PNP and P-channel MOSFETs are not too much of a problem, but you can still find better specs for NPN and N-channel in the datasheet. The main difference is with the 'majority carriers', either free electrons (for NPN and N-channel FETs) or free 'holes' (missing electrons for PNP and P-channel FETs). Electrons move quicker through the semiconductor material than holes. Hence low side switching with transistors is usually preferred.