I suck at doing several things at once. I get very annoyed if I have to keep track of several unrelated things at once.
For example, if I'm trying to install an operating system and someone calls me, and I continue paying any attention to the installation, I get annoyed every time the other person says anything. Likewise, I am annoyed every time the installer asks any question from me, while the other person is talking.
Sometimes I need to juggle many things: installing an operating system, while cooking lunch, and answering several unrelated phone calls and text messages. I should just make a note of all other other things and ignore them while the stove is hot. When I don't, I ruin the lunch, yell at people on the phone, and forget to make a separate /boot partition.
There is a way to multitask effectively, by using machines to do things for long periods of time without any attention from me. For example, dish washers. I love that I can spend a couple of minutes setting it up, and then ignore it completely until a couple of hours later when it's done.
With computers, I can start long-running batch jobs of various kinds, which I can ignore until they're done. For example, batching many small file transfers into a single command.
Unfortunately, networks and computers have become so fast that my multitasking opportunities have significantly lessend over the past couple of years.
But perhaps that just shows that I haven't automated my life enough yet.