The answer to 'why is my toilet slow draining' is that the toilet drain is likely clogged or obstructed. Common causes include accumulated toilet paper, debris, or a buildup of mineral deposits over time. Symptoms include the toilet bowl taking a long time to empty or water draining slowly.
If the toilet is only slightly slow, you may be able to fix it yourself using a plunger or a toilet auger/snake to clear the clog. However, if the drain is severely blocked or you cannot clear the clog, it's best to call a professional plumber. They have the right tools and expertise to properly diagnose and fix the issue without causing further damage.