It's on the extra mile where success is obtained. The key is to just keep moving forward, despite the number of times you fall. If you knew success was right around the corner, wouldn't you keep going? How do you know success isn't within your reach? The only way you lose is by quitting. The definition of commitment is doing the thing you said you were going to do, long after the mood you said it in has left you.
Studies show that the human mind can only truly multitask when it comes to highly automatic behaviors like walking. For activities that require conscious attention, there is really no such thing as multitasking, only task switching - the process of flicking the mind back and forth between different demands. We're just doing one thing, then another, then back again, with significantly less skill and accuracy than if we had simply focused on one job at a time. The end result is the same - performance quality suffers and all activities take longer to do than they would have if a single task had been the sole focus. Multitasking is a productivity drag masquerading as an efficiency booster.