Based on the probabilities, just watch a football match for example, you have team A with odds of @1.10 and team B with odds of @20.00, you can easily see that team A has a much greater chance of beating team B. If you are betting on the underdogs with odds of @10.00 you will see that you will miss many games without getting it right, while when you bet on the favorite teams with odds of @1.10 you will see that you will have many hits, but the problem with this is that in the long run you will not make a profit.
This is when the odds are difference is too obvious that Team A has a better performance than Team B with a huge margin, mostly see these odds in rare cases. In most case in football the odds are either, 2.43 against 3.43, 1.89 against 4.22 and so on. Anything can happen in games where the odds are like this, so you cant be so sure Team A will win Team B, that is with absolute certainty.