The answer to 'why is my toilet' is that there are several common causes for toilet problems, including clogs, leaks, flushing issues, and water supply problems. Symptoms may include the toilet not flushing properly, running constantly, or water not filling the tank.
Some common solutions include plunging the toilet to clear a clog, tightening or replacing the flapper valve, adjusting the water level, or checking for leaks in the supply line or around the base of the toilet. For more complex issues, it's best to call a professional plumber who can properly diagnose and fix the problem.