In sports, there is always someone winning dominantly. It can get to a point where they are almost always expected to win. By that point do you continue to bet on those favorites to keep winning or does it bore you? Would you enjoy stirring it up a bit just for the fun of it and betting on the underdogs even if the chances are quite low?
Sometimes it is good to continue betting on the big teams that wins dominantly because even if they fail, they can still make it up unlike the underdogs that can only win once in a while. Let's take for example Liverpool and Manchester City last season. Liverpool didn't lose many matches last season and they remained at the top of the league from the beginning of last season till the end so imagine someone who is betting against them in most of their matches, isn't that going to be a loss to the person? let's also talk about Manchester City, last season was not one of their best but despite that they had some lapses at some point in season, but they still pick it up and gained form again so someone who wanted to take advantage of their weakness and bet against them in every match will end up being at the losing side.