To me, this is a bad habit of mine that I will not throw away any time soon. Sometimes it works perfectly when dealing with tasks that require different level of focusing. I consider three tasks at one time doable (and normal, for me). Read once before that the more you do, the more your focus will be divided (=less for each task) so doing more tasks might not be beneficial. 

LOL.. why do I sound like the beginning of a How-to article? 

Not doing that. This topic just came up in my mind at noon. I don't really like multitasking but it helps getting things done efficiently. As long as it's a reasonable number of tasks. The real challenge is when you're "changing gear" back and forth from multitasking to being focused on one thing. I get distracted easily at times but there are moments where I get into the zone. I think going back to reading physical books regularly this year helped me develop back that focus-on-one thing. At first, it was hard to read for a long period of time. I think I'm better at that now, months later... but probably not as good as before [the reading slump]. 

Was checking this before publishing and the part "don't really like multitasking" is bugging me. I don't particularly hate it. I just don't like that I'll have less focus when I do more than three tasks. I think I'd come to embrace and like it when I multitasked at work (the job really required the skill if you want to get anything done *sigh*). I guess I only like multitasking when it works (advantageous & efficient) ...? Since doing too much at one time beats the purpose (I might make more careless mistakes). I'm more a fan of being able to switch between those two smoothly because each has its own uses.