I enjoy making bread, but the bread I make using standard yeast of course lacks that sourdough taste.   But the process of making and maintaining a sourdough starter frankly requires a bit too much work and consistent attention from me.  Is there a way to approximate that sourdough taste using a process less complicated and high-maintenance than a "real" sourdough starter?   (As a footnote, ideally this would be a process that could start the night before one made bread, but not much more than that). 
Some companies sell a "Sourdough flavor" that is usually just sourdough waste products, some deactivated yeast, and filler. The waste products are what you usually taste in sourdough, so these might be somewhat effective.  Since a lot of the flavor is from acids like lactic acid, you could try adding something else that contains lactic acid. The juice from fermented pickles, sauerkraut, kimchee, yogurt, etc... should all contain some lactic acid and may give you a bit of the flavor you're looking for. These may contain other flavors though, so be sure they won't conflict with what you're trying to do. For instance, kimchee frequently has garlic in it, so if you don't want the garlic flavor in your bread in addition to the sour flavor, be sure to find a kimchee that lacks garlic (or has less). 