Luckily, in most cases, this is a DIY repair requiring only a few basic tools. If your door sticks at the top, the issue may be due to a misaligned door frame, loose hinges, or swelling of the door.
How to fix an annoying sticky door fast? You could plane the top, restoring the gap and reducing the door frame rubbing. But what, then, should you do about the gap at the bottom of the door?