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, water continuously running, or the toilet bowl filling up slowly.
Some common causes and solutions include: a clogged drain line (use a plunger or drain snake to clear the clog), a leaking toilet (check the flapper, tank-to-bowl gasket, or supply line for leaks and replace as needed), or a problem with the flushing mechanism (adjust the float or replace the fill valve). If you're unsure of the cause or don't feel comfortable making repairs, it's best to call a professional plumber to diagnose and fix the issue.