My MIL is lovely, really really nice, and she didn't say it to be nasty, but she claims that she didn't hear of two year olds having any more tantrums than other children, and certainly never heard the phrase "terrible twos" before DH and BIL were about 10 or 11 (so mid 80's)
Me and my sisters started being born around then, so I can't really ask my mum.
Surely it isn't a societal construct? Surely?????
(mother of a very strong willed 2yo DD)