The answer to 'sink overflowing' is that a sink overflowing is typically caused by a clogged drain or a problem with the sink's plumbing. Symptoms can include water backing up in the sink, water spilling over the sides, and potentially water damage to the surrounding areas. Common solutions include using a plunger to unclog the drain, removing and cleaning the sink's P-trap, or using a drain snake or auger to clear a more stubborn clog.
If the sink continues to overflow after trying these DIY methods, it's best to call a professional plumber. They can diagnose the root cause of the problem, which may be a more serious issue with the plumbing system that requires professional repairs.