The plunges are fun to see, but I am not interested in betting in markets of 160% or following a horse I know little about (or little about the others) because some optimistic owners are throwing away their money.
Even if you are confident, and it is usually based on knowing your horse and ignorance of the other runners, the plunges by owners often prove costly because they are usually taking unders to start with in markets of 150%.
But it's fun watching.