For most casual sports bettors, making a bet on a game has less to do with careful analysis and seeking the best value for their bet and more to do with simply wanting to increase their excitement and interest in a particular game.
For the professional sports bettors, enthusiasm for a game is a distraction while they are gathering and studying information looking for advantages where the book has a bad line on a game or is behind in updating a line for new information related to a game. Then there are my favorites, the math geeks who just look for opportunities in the wide range of lines available or connected to a team and or a particular game and look for opportunities to get plus money on both sides of a game.
Often times professional bettors are stigmatized as guys who are either trying to manipulate a betting line, or that pay for secret information on a team or players, or in the extreme that they might even fix a game or even try to delay when the books might learn of an important piece of game related information so that they can get a bet down first. In the old days (before cell phones and internet), when you got a piece of useful information you could take a little time to figure out how to best use the information, presuming the information of course was good. Which begs an interesting question “when is advance information cheating or not or is it simply survival of the fittest.”