It seems plain enough that science, engineering and religion all had the same genesis [pun definitely intended]: Oog got tired of Nature shitting on him on a more or less regular basis and asked himself, 'What makes this happen to me? What can I do to make it happen less?' Oog may have noticed that Skrg - for example - threw things at the sky to make it stop raining on her. Sometimes, it appeared to work. Maybe there was something in the sky that made the rain, and it could be threatened or cajoled to make the rain stop (or at least rain at a more propitious time). If flinging sticks and other bits of rubbish at the Make-It-Rain thing didn't work, perhaps something else would. Maybe the Make-It-Rain thing was hungry, and if it was fed it would feel better and stop the rain.
Giving extra food to the MIR thing worked sometimes, sometimes not. But Oog also noticed that he got less rain on him when he was under the trees. Since lugging the forest about with him on the off chance of a thunderstorm wasn't practical, there might be a way to make a little forest he could run to when the MIR thing went all drippy, sacrifices or no sacrifices.
And so on and so on and so on up to the present day, where everyone is consumed with clickbait.
Boru
Giving extra food to the MIR thing worked sometimes, sometimes not. But Oog also noticed that he got less rain on him when he was under the trees. Since lugging the forest about with him on the off chance of a thunderstorm wasn't practical, there might be a way to make a little forest he could run to when the MIR thing went all drippy, sacrifices or no sacrifices.
And so on and so on and so on up to the present day, where everyone is consumed with clickbait.

Boru
‘I can’t be having with this.’ - Esmeralda Weatherwax