Sometimes it's possible & beneficial to do two things at once. For example you can play an audio book or enjoy music while walking or watch TV while working out. However there are times when it pays to single thread. For instance you should not be talking on a cell phone or texting while driving.
Sometimes multitasking takes more time than if the tasks were done one by one & yields poor results. Recognize which method is suitable for which task. If you can multitask the items great, but if you are trying to multitask & know you should be single threading STOP do one thing then the other.