For starters, over/under bets is a type of sports betting where bettors try to predict whether a combined number of score of both teams is over or under a predetermined value. It is observed that beginners tend to bet on the over side. Why? Because over means excitement.
Over or under betting is not limited to both teams. There is always some individuality to it where you could pick a particular team to score over or under a defined goal range, be it over 2.5 which means 3 goals and above or under 2.5 which means 2 goals below.
However, having to decide when to patronize this market in sports betting is far from anything excitement. It has its own thrills you know and depending on how you know the teams, what league and at what stage they are in the competition, this is usually a choice when the win market seems a lot tricky.