I used to say to my mum "why are you wearing a lip liner, it looks weird!" granted she did
If I'm wearing a nude lipstick - MAC's Velvet Teddy still being a favourite then I don't go without a lipliner. My lips could 100% do with being a little more plump, so I can't resist slightly over lining. The NYX Liner in Mauve is the perfect dupe for MAC's Whirl and a fraction of the price, they both provide a deeper nude/ mauve shade, very 90's so if you love that trend and don't have these liners then you won't regret buying them.
An absolute bargain is the MUA liner in Caramel Nougat, perfect for someone who is wanting a nude lip liner on a budget, granted it doesn't last as long as the MAC liners but still worthy of a mention. This is more pale in colour but still carries the nude tone like the other two mentioned, I love wearing this why Shy Girl by MAC.
I am still on the hunt for the perfect lip liners to match some of the brighter lipsticks I have e.g. Morange by MAC - which I am still too scared to wear!!