I had very constructive arguments about this with my grandma :

• Can you fetch one the green tiles ?
• What green tile ? You only have blue ones.
• Goes to fetch it herself. See ? A tile, and it’s green.
• But it’s clearly blue…
• I don’t know what you mean, can’t you see that it’s green ?
• I can see very clearly that it’s blue.
• No this is green, this is blue, and the tile is closest to green.
• It isn’t though, it’s definitely closest to blue.
• A while later
• This is pointless… Let’s just call it turquoise.
• Turquoise it is.
• The next time
• Your new oven mittens are quite nice, the blue goes well in your kitchen.
• They are green…