What are the things one can't do on a tablet as opposed to desktop and maybe laptop?

I’m guessing that you meant to type, ”...desktop and maybe laptop?” If yes, you might want to edit and clarify.

Playing World of War Craft or other similar games.

I give up sometimes trying to type in complete sentences without a physical keyboard.

For example, mostly I respond on Fluther when I am using a computer. I might read the questions on my phone, but I answer when I am sitting at a desk.

Yes, I am old, why do you ask?

* Have a large high-resolution screen.

* Have multiple large high-resolution screens.

* Play high-requirement games well on a large high-resolution screen.

* Have powerful graphics cards.

* Use a real physical keyboard without defeating most of the purpose of the form of my device.

* Have multiple high-capacity high-performance hard drives that store everything I want.

* Have huge amounts of RAM for fast computing, gaming, photo manipulation, etc.

* Have other built in full-size drives, burners, network and other devices, etc that can be swapped in and out.

* Run software designed for full computers with full displays & specs.

* Dual-boot Linux and Windohs 7.

* Easily avoid all sorts of unwanted tracking/spying attempts via built-in webcams, GPS, etc. and not have to void my warranty if I want to install whatever hardware or software or have root access.

* Easily install software that doesn’t go through a “store” app.

* Hold down my desk.

* Generate dust bunnies.

Difficulty hitting “Right Click” without a mouse

I have an Ipad and kinda like it. I can do everything on that device as I can on my laptop only at a slower pace and all because I don’t use it a lot. I watch millennials tear it up on their tablets at a dizzying pace so I am sure all I need is more practise.

Difficulty hitting “Right Click” without a mouse

Long press brings up the right-click menu.

I agree with @Call_Me_Jay about using a real keyboard. I often write research memoranda, and I can’t imagine creating a Word document on anything but a full-sized keyboard. I learned how to type in high school. That was a long time ago, and I’m certainly not a touch-typist any longer, but I still use the same techniques.