Although the potential payouts look tempting - many sports bettors have dreamt of cashing in nearly $10,000 by nailing a $10, 10-teamer at 850/1 - they are a bad bet because they are difficult to hit and do not pay anywhere near true odds. This is how the sportsbooks make a lot of their money. For instance, let's say you want to bet a two-team parlay. For two games, there are four different possible combinations of outcomes, thus the true odds are 4/1. However, the sportsbook is only going to pay you 2.6/1 for your efforts, thus giving them a "juice" or vigorish in their favor. However, if you only have $20 to your name for a football bankroll and really like two games, the two-teamer might be the way to go because you could win $52 for your $20 wager.
The point spread is a handicap placed on one team for betting purposes only, it has no place in the game itself. It's designed to give both teams an equal chance at winning in the context of wagers. Think of it this way: If last season's Super Bowl champion was playing a basement-dweller team that hadn't won a game all year, that's a shoo-in bet. Of course, you're going to take the Super Bowl champs, and in all likelihood, you're going to win. What's the fun in that? Even your bragging rights would be next to nil.
That was all before Charles McNeil, a math teacher from Chicago, invented the concept of the point spread. An avid gambler, McNeil created what he called “wholesaling odds” and started his own bookmaking operation in the 1940s. He started out offering this new style of betting on football, but his business model grew to include basketball. McNeil changed the way sports betting was done, and his legacy lives on today in what we now call the point spread.