At random

Just try to let ink drops fall into a glas of water and you'll see some obviously random form — or highly unpredictable.

Is it convenient to qualify such a practice as hobby, a cool one, but vain ? I'm not sure... because I don't believe that it's a pure random process.
First, as your practice grow, you'll be able to produce a determined type of form, prefered to others.

Another major point : you're taking picture from a continuously changing form : the instant is your choice and your choice only as decisive.
As an objection, can be standed  that we're considering a very short process — only a few seconds — so brief, that reflection can't take place.
Quite true ! That's why this practice has to be considered similar to écriture automatique, a surrealist creative practice.
By the way, it's amazing to see how some of these pictures seem familiar to some of these painters.