Most of us cut the label off and throw it away, without even reading it. Yet that small card tells you a lot about the product that the seller does not.
The first thing to look at is fibre content. "Cotton-rich" and "100% cotton" are not the same thing. A product labelled "60% cotton, 40% polyester" behaves quite differently in feel, breathability and pilling. The second is the wash symbols. They are information the manufacturer gives after testing what the product can withstand. If the symbol says 30 °C, washing it at 60 °C is your choice, but the responsibility for the result is yours too.
The third is size and weight, and the fourth, if there is one, the certificate number. Then there is the country of origin. This is not about nationalism; how deep a country's manufacturing tradition runs in a given product group also affects quality. Reading a label takes a few seconds. Not reading it can sometimes cost years of disappointment.