I'm in my early 30's and only just found out this was a thing.
Always found Muesli hard work desu, but accidently left some for an hour then ate it and it was fucking great.
Did a google search for soaking Muesli to see if id discovered something and it turns out its been a thing all along, in fact you're kind of supposed to do it.
In the pic, some Muesli that has been soaked overnight in yogurt.
So has soaking Muesli been common knowledge this whole time?