Tapering is the hardest thing to do for most runners. Usually, it's done one to two weeks before a major race and the runner is to decrease their mileage to a very low number and effort. This seems like a deal, but to runners, it can be excruciating. All those months of training have made it intuitive to run and run with purpose. To lay off, doesn't feel natural. It almost feels like giving up. In fact, most runners will be irrational and think that by tapering they will lose their ability to finish the race or lose some endurance they have worked so hard to build. You can equate it to cramming for a test the night before. Cramming never is effective. You are too tired the next day do grab the answers from your brain. The same goes for running. You have to trust that the training is working and that all your body has learned is still there to get you across the finish line. It will not be those last few days of pounding out unnecessary mileage and effort that helps you do it.