People's tastes vary. There’s no definitive measure of quality better or worse way to enjoy something like tea. British tea tastes may be different to what you appreciate, but that’s nobody’s problem but yours.
This is a good point - there's very little objectivity in "quality" when it comes to flavour, as theoretically some group of individuals could prefer a bitterer/sweeter/sharper tea than others. It's often cited that the taste of chocolate favoured throughout the world is very regional e.g., but clearly in some places this could be due to the quantity of some cheap ingredient such as sugar. Quality of inputs, or the method of growing etc. are probably more quantifiable.