For an anniversary gift, a few years ago, we were given a smoothy maker. 'Great', thought I, I love smoothies and now I can make my own, with the fruits I like the most, raspberries, loganberries, gooseberries and so on and so forth.
At the time 1ltr of a popular brand of smoothy cost around £1.50 from most supermarkets. I now discovered, to my horror, that the cost of sufficient fruit to make around ½ltr of smoothy was coming in at around £5. Needless to say, the smoothy maker has been consigned to the back of that kitchen cupboard where similar useless stuff is stored until the day it is either flogged in a boot sale or heaved in the bin.
What reminded me of this was BC's curried tuna. I do, all too clearly, recall making a smoothy from cucumber, which I find a very refreshing salad ingredient and is, after all a fruit. I don't think I have tasted anything so vile in my entire life.

I'll add smoothy makers to the list of bad inventions.