If I’m not mistaken, this isn’t allowed any more. You now have to have a neutral at the box, so instead of using the neutral in that manner you’d have to use 3-conductor cable.
I also used it most recently to repair the outer sheath of cable that I had caught with the edge on my hammer while stapling. Individual insulation was fine, just a couple wraps around the outside.
Electrical tape. What is it used for?
Absolutely nuthin’, say it again.
Good god, y’all.
Maybe so, but if you’re wiring up a 240V appliance in the US, you can run regular romex and mark the white wire with black tape. So the white and black wires are now both hot, and the ground wire is still ground. You don’t generally need a neutral - some appliances want the neutral so they can use 120V inside as well as 240V, but I suspect that this is rare, since it is straightforward to convert 240V to whatever voltage you need.
I use it to cover soldered splices when heat-shrink tubing is impractical (or when I don’t have any of the right size). I also use it to make a water-shedding cover for cable junctions that might be exposed to weather.
I’ve also seen it used by male cosplayers at conventions in venues that have a gender-neutral no-nipples rule.
Already mention wrapping wire nuts in crowded boxes, low voltage connections, and marking 240V wiring. I also wrap the wire nuts in outdoor boxes for extra moisture protection. Also had to use a high current aluminum to copper connector that had to be wrapped in silicone tape and then covered in electrical tape to hold it all together. I wrapped splices for welder cables with it. At times I’ve used it to temporarily hold wires together while sorting out a crowded box. And it’s just good general purpose tape.
Racing Stripes.
Electrical tape. What is it used for?
To wrap around the muzzle of my dog when she barks too much.*
…and on my ex, for pretty much the same reason.
*just kidding…too much of an animal lover to do that.
Why? Is it just not as effective as one might hope? Or does it have side effects that make other means of insulation preferable? Or is it that the very project of insulating tool handles i itself a bad idea (this one seems unlikely, but just wanted to make sure I covered all the bases)?
Right, IOW, the only commonality between electrical tape and hockey tape is that they are both tape, usually colored black! 
The salient characteristic of hockey tape is a durable, rough, high-friction surface.
Covering up the LEDs and backlit ASUS on the front of my PC. It makes enough noise when it’s running, there’s no way I need light bright enough to read a newspaper by to let me know it’s on.
Friction tape was cloth soaked in asphalt and was used as insulating tape.
Anyways, ten-speed bikes used to have Maes handlebars which were covered with thick plastic tape-grip material. I found plastic electrical tape stayed on much better.
Other than that, I also used to do a lot of car stereo work on my old beaters. Twist and tape worked every time. Speaker connections were soldered, of course.
Or gaffer tape, which looks almost just like duct tape, but without the ultra sticky mess. Of course, it comes at a premium price compared to duct tape
Electrical tape comes in many, many varieties, with equally many uses.
The standard black vinyl tape is ideal for repairing the sheathing on extension cables after they have been properly spliced - several layers of tape, starting far down the cord, and wrapping tightly at first, then gently at the last layer, so that it doesn’t tend to unwind.
As mentioned above, there’s friction tape, which is pretty useless for electrical work, but makes great handle grips.
Recently I found the holy grail. Apple uses this, thin, yellow super-adhesive tape in their laptops (to hold cables in place). I finally figured out what it is (Mylar tape), and bought some. It’s great for computer repairs.
This! Makes the life of other trades during renovations and new construction that much easier. I see it as the mark of a responsible electrician that understands the needs of other trades and future electricians.
I am going to go out on a limb here and guess that you have never actually touched a hockey stick or hockey tape.
I don’t know which particular issue Chefguy is thinking of, but electrical tape tends to ooze a little of its glue around the edges, especially under pressure or when warm. This makes it seal better, so it’s a useful feature for many applications, but wrapping around handles is likely to make them perpetually sticky.
Dip-coating handles is a better solution, and products for doing so have been available for quite a while.
My husband uses it to secure wire nuts in junction boxes.
God yes! I have a generic USB power supply wall wart with an electrical outlet and two USB outlets on it. I thought it would be great for charging my phone and iPad in my bedroom until I realized the blue LED was like a full moon on a clear night. Fixed by a small piece of black electrical tape.
As an electrician I’d use it to color wires, attach wires to fish tapes or pull strings, hold things in place, as a weight for throwing pull strings. taping off wires temporarily(as opposed to capping them with a wire nut), occasionally tape outlets in metal boxes, tape up signs.
Doing well work I go through more electrical tape in a week than I ever did as an electrician. I order it by the case. A case has 240 rolls. We use a majority of it taping submersible motor leads to the drop pipe in the well.
Outdoor extension cords.