'Must' commentaries for creative challenges

I've been experimenting with this 'must commentary' approach to creativity. I'm posting to see if anyone can bounce back any thoughts or ideas.

The must commentary

With this approach, I consider an activity - such as posting a Christmas card through someone's door - and run through the stages visually in my mind. As I go, I apply a 'commentary' in the format:

I have to...

So with the activity of posting a Christmas card the commentary could read:

1) I have to watch out for cars
2) I have to cross the road
3) I have to walk down the pavement
4) I have to spot my friend's house
5) I have to open the gate
6) I have to walk up the pathway
7) I have to open the letter box
8) I have to push the letter in
9) I have to walk down the pathway
10) I have to close the gate
etc

I can also consider the ultimate outcome of all these actions: my friend gets a Christmas card.

Enforced limitation

At the next stage I consider how I could still achieve my objective if one of the stages were prohibited. So if action 6: walk up the pathway is prohibited how can I achieve the next stage - section 7 - of opening the letter box? Or alternatively, is action 6 is prohibited, how will I achieve the final outcome: my friend receives a Christmas card?

So far I've found that experiment with this technique can be very thought provoking and stimulating. The considerations from the above scenario actually led to a concrete idea I submitted to the Global Ideas Bank:

A person in each street to take in parcel deliveries

Refining the commentaries

Something I want to look into soon is refining the commentaries. So with the Christmas card example I could create a 'hand must commentary' where I would state the mandatory actions of my hand during the posting of the card. There are obviously endless possibilities for developing this approach.