Every time a human does something something they were not programmed by self motive and self preservation, it seems to me they get strengthened or super-positioned into multiple time lines. As their actions were not expected as a future possibility, so a new timeline seems to have been created.
So the proposition is that when humans do something selfless their future changes.
About 30 years ago I had to choose and I saw 2 life paths - one was muffled and constrained and the other was a wild path. I chose the wild path and it has been pretty wild but I do not regret it.
I am not sure that that was really creating a new time line as compared with choosing to manifest one time line as compared to another.
In that case the time lines were very different, but in our daily lives often the time line options are very similar.
Does crossing the road at a different place produce/activate another time line that usually rejoins the time line in which the crossing occurs at the regular place?
I suspect that there are many physical-world time lines and that humans can cross to and fro without necessarily realising it.
That might be one reason for losing things and finding them exactly where I looked. The object is there on one time line but not there on another.
For example, I was once living alone and went to the fridge for a bottle and could not find it there. I ducked down to look across the largely empty shelf to see if it was there. Its absence was so strange that I put my arm in across the middle of the shelf and moved my arm around in case it was there but invisible.
An hour later I was back at the fridge and there the bottle was - in the middle of the front of the shelf where I had looked - exactly where I had put my arm in.
I thought of a poltergeist but the usual pre-conditions were not present, there were no poltergeist symptoms, and no sense of another entity.
The only other theory I can find is the idea of multiple time paths that humans hop across mostly unconsciously. That sort of hop could give a sense of deja vu.