Tides are caused by the specific alignment of the Moon, Earth, and Sun.
When aligned a certain way the the gravitational pulls basically share and add on to each other creating tidal waves.
An example of a certain alignment would be spring tides, which happen during a New or Full moon.
Examples: Boat sailors must watch out for tides and make sure to plan their sailing journeys according to the tide. They don't want to be caught against a tide, especially small board sailors.
Also fisherman keep note of tides since some sea life rely on tides for survival and feeding or some fish simply follow the movement of the tides. Fisherman use tides as an indication of when it'd be best to go fishing.
