Tight lines is an expression often used among fishermen. Why? Because your fishing line is an important connection between you and the fish. If the line has slack in it you will never know exactly when the fish bites your bait. The fish may even have a chance to spit the hook out if it doesn't like the offering or it feels the sting of a pointy hook. A slack line can be caused by not winding in excess line after a cast or when you don't have enough weight to hold bottom when bottom fishing or when a boat position shifts because of wind, current or changing tide. Whatever the reason, it is important to get and keep your line tight.