A carrot is not just a carrot. They come in many sizes and shapes. Some are orange, some are yellow, and others are red. Some are even white or purple.
Also the taste is different. Some carrots are mild and sweet, while others has a stronger taste, and some are almost bitter in taste.
Here you can see a small selection of the many different varieties that exist:
Going clockwise from the large white root the varieties are Belgian White, Juwarot, Nutri Red, Gonsenheimer Treib, Jaune de Doubs, Rothild, Nantes 2, Flakeer 2, Géante Rouge, Imperator, Chantenay Red Cored, Rodelika, St. Valery, Rotin, Regulus II, Kämpe, Pariser Torve, Amsterdammer 3 and Rote Riesen 2.