Why do they never believe you until they have tested it for themselves

Okay so we go shopping and make our way around the isles. Something catches my 3year olds' attention.

'I want that one' he announces.
'You won't like it' is my reply.
'I will like it it's green like Ben 10. I want it Mum, I'm thirsssssssty!'

I pick up the product in question, I scan the label. Go Coco, Coconut water drink. apparently it's Natures Sports water. No preservatives, natural colour and flavour, I scan the ingredients and nutrition panel and no longer object to the purchase...

'Alright, but you won't like it' I warn.
'I'm telling you Mum I will love it' he scorns defiantly.

Our trolley is less than 10 meters from the store before his head is diving into the bags scouring for his prized win. Eureka he's found it.

'Open it Mum? I'm thirsssssssty'.

I obligingly twist off the lid and remove the foil safety seal before handing the bottle over to his excited grasp.

'Yum!' He declares before the drink has had a chance to register with his taste buds.

'Humph', perhaps I was wrong. No matter if I am, it seems like a pretty nutritious product.

We head home and unpack the remainder of our purchases. (Well I'm unpacking, he's acting as quality control).

He perches himself at the breakfast bar with a tub of diced fruit and his bottle of Go Coco. He takes another swig and shudders.

'Mum I really love the colour, but the flavour isn't as good as something else'
'Don't you like it Alexander?'
'Yeah I do, it just doesn't have a good flavour'.

I take a swig myself in jest, and almost spray the product across my kitchen.

'Ugh! Next time we're at the shops and I tell you that you won't like something, will you listen to me?'

'Okay Mum, can we put it in the bin now? It's a really good colour but I think it tastes just a little bit yuck. I think they left out something because other green Ben 10 drinks taste so good to me'.