Nail polish

So yesterday I painted my nails with the new varnish I bought, really nice colour actually :D and HM is cheap as well, and good, so for you who don't have the budget and love to change colour all the time it is perfect! I don't understand people buying nail varnish from Dior or another big, famous brand. What makes them better? And £20 more expensive than a normal one? Just a waste of money really as no one can see the difference. But I guess it depends on the individual and if they want to spend their money on ridiculous stuff (I'm not the one to talk really haha, I spend all my money on ridiculous stuff ;) )