I have been taught and/or tried out a lot of different methods for caramel sauce. When I got into vegan baking in the early 2000s, I usually relied on sugar, vanilla, salt, and water. I learned a few more complicated methods involving heavy cream and butter in culinary school. Professionally, I've worked with at least a dozen different chefs in Grand Rapids that have shown me different ways.
Working at Propaganda Doughnuts with Tory O'Haire (The Starving Artist, Downtown Market, Grand Rapids Cocktail Guild, and other elite responsibilities), I was able to use different chocolates, fruits, spices, and molecular gastronomy in caramel making. The old method of 2 parts white sugar to 1 part water in a sauce pot over medium heat was refined with Tory's methods. While the solution reduces just to the point of burning--the actual requirement of caramel classification, anything less being butterscotch--we used a pastry brush to keep crystals from forming on the sides of the pot. The molecules in caramel are much more likely to crystallize in the presence of other sugar crystals, and if this chain reaction kicks off it could lead to ruined caramel and a ruined pan.
Caramel is pretty amazing, in taste and scientifically. Starting with sweet, but near flavorless, sucrose in water, heat breaks the sugar down to glucose and sucrose as the substance darkens and develops new flavors and aromas. Fine Cooking has a very good explanation here.
For every opportunity I've had to watch caramel making, make caramel myself, or even hear a story about caramel being made, I've experienced more that turn out poorly--short of on fire, It could suffer being burnt, undercooked, crystallized, or countless other deaths. But I've also learned more during these experiences than when it turns out.
You don't always throw out messed up caramel. If it doesn't taste like charcoal, you can salvage it by adding different ingredients to improve taste and/or texture. If you find yourself fixing messed up caramels on a continual basis, you learn how to improvise, and temper things, and eventually work off book. I suppose there's a metaphor here.