Beans
Bread, has to be hovis unless it’s a farmhouse or tiger loaf
Washing pods, used to use Tesco non bio until all the clothes kept coming out stinking and covered in grey silt-the colour changed from blue to white and I swear they completely changed the formula as I’d used it yrs up to that point.
Cola/pop all the cheap own brands versions taste so weird and have a twang to them.
Teabags, have tried with loads of cheaper own brands and cant bare the taste has to be Pg tips.
Nappies, when my kids were in them, pampers all the way, never had leaks, didn’t need changing as often as supermarket own packs, had neighbour who would swear by them(kids same ages) but she would end up changing her dd several times a day due to her ended up soaked, never happened with my dd.
Cheap sellotape, cheap fairy liquid, same reasons as previous posters.