Heroes– focal characters if you prefer– do not sit on the couch or stay at home very much. They go out and DO all the things that most readers either WISH they could do, or could do, but don’t have the time/money/energy for whatever reason. Hence, we read about them. Now, while it may be possible in life that crazy people do things outside their houses for absolutely no reason at all, this does not keep a reader interested or make a good story. Actions not only must have consequences, they must have a motive. Consider this….you might…on a whim….go for a walk. Lots of people do this. However, you might make a rule that whenever you approach a fork in the road, you “flip a quarter” and heads you go left, tails you go right. Seems rather random, doesn’t it? Sure….but that’s not why we’re going for this walk. We’re going on this walk for entertainment– spontaneity even. Something fresh, different, and new. So for any good yarn to come alive….the focal character really needs not one motive, but several, both present and future.
To make a list of the Seven Deadly Sins (pride, gree, lust, envy, glutton, anger, and sloth) would be a good start and a list of “core” reasons as to why people do things, but it would be doing your characters a disservice…..for example….other motives are and not limited to…..
Revenge, Justice (see the difference there? To the extremes, the latter implies having someone arrested, the former implies vigilantism). Love, Power, (bare) Survival, Adventure, Boredom (and the want to alleviate that condition), Ambition, Romance, Sense of Security, Fame, Children, Cheap Thrills, Altruism (The simple desire to be good and live life to the benefit of others), Religion (or lack thereof), Patriotism, Self-Destruction.
With some soul searching or meditation, anyone can increase the list by asking him/herself why they do the things that they do. When a focal character has more than one motive (going to the diner to apply for a job and, oh, by the way, meet a member of the opposite sex at the same interview), that’s when things get more entertaining for the reader– and for you.