Before you use your laptop or phone, write down exactly what it is that you want to achieve. Then, time how long it takes, and recall exactly what it was you did end up doing.

As you say, the results are surprising. I have worked very hard to remove tech from my personal and social life as much as possible.

Edit: youtube is the worst for this. I know perfectly well that 99% of youtube videos could be summarised in a few sentences, yet still find myself watching endless rubbish.