Animation can be used to tweak the user’s perception of time, so use this in your favour. For the human brain, anything below 0.1 seconds will seem instantaneous and below 1 second will seem seamless. So, if you have a process that takes 6 seconds for instance, you can break it down in a few separate animations. This trick should make the process feel a lot faster and keep your user engaged.
You can also use animation to fake an instant action that will actually take bit longer in the background. This will make the app feel more responsive even though the process still takes longer than what the user sees.