Distractions.

A truth that most people won't tell you is that no matter what you do, you'll have big odds of being distracted by people. Some or the other person will always want or need your help or attention and you'll invariably end up giving them just what they want, even if you don't really necessarily want to do it. Sometimes you do it because it's the polite thing to do, sometimes you do it because it's the right thing to do. Either way, what you'll end up doing is losing track of your own schedule and start lagging behind. And believe me when I say what it feels like to be frustrated because of a random person's intervention in your life without any announcement. It happens all the time for me too and my patience at times, wears thin. However, there is one way, and I'm confident it's the only way too, to deal with it. It's not really rocket science, just anticipate it, like you do know already, and allocate some time for it, perhaps an hour two for it. Design and plan your other tasks around it. Make sure you don't spend too much time on the distractions or too little time. Just the right amount would suffice and with time, you'll get better at it. 

Love, peace.