5yo DD1 has always had a thing about things being 'tight' - eg when she was 3 she had a pair of velcro sandals that she always wanted done up so tight to the point they were leaving marks and even then she would have a meltdown because they were 'not tight enough'. More recently it's been her school summer dress, which has a tie at the back- she has frequently thrown major strops in the morning if it's not tight enough. And I recently had to confiscate a goldilocks dressing up outfit because we had the same problem with the little pinny never being 'tight enough'.
At a day out yesterday at a local nature reserve she had a huge tantrum and pretty much ruined her whole day because they gave the kids little backpacks with binoculars, magnifying glass etc and she just kept making us adjust and readjust the straps to make the backpack tighter and kept throwing tantrums.
She is generally pretty well behaved (though I admit she has been having more tantrums this school holiday than ever before) but I just don't get this issue with tightness. Will she grow out of it?!