Why Do Moments of Mindlessness Occur? I noticed that at key moments, such as when I am using social media in a passive way, or when I am between tasks in daily life, I tend to enter a kind of 'habitual' mode of being. On social media I click aimlessly around, almost compulsively. In my house, I just walk around without much planning or purpose. 

What could cause such mindless behaviour? 

I am also wondering whether merely paying close attention to lapses in attentiveness and to distracted moments can ultimately lead to the elimination of such habitual behaviours.
In short, the five hindrances disrupt mindfulness. 

https://en.m.wikipedia.org/wiki/Five_hindrances

Also related to the five hindrances are the general defilements (kilesas), which also hinders mindfulness. 


  I am also wondering whether merely paying close attention to lapses in attentiveness and to distracted moments can ultimately lead to the elimination of such habitual behaviours.


It’s a good start. However, one needs to purposely commit to the entire eightfold noble path in order to completely eliminate those behaviors.