Always assume that people will do mistakes when they use your app. This means, that people will tap or click on buttons that they didn't want to click, or that they'll make mistakes when entering data.

To avoid that people get frustrated by their own mistakes here a  few things to take into consideration:

Help me go back

Users should always be able to go back. If they are in a task manager app, they might click on a task to edit it. But then they might change their mind. So they'll need a little "go back" button that brings them back to where they where without forcing them to change the task that they opened.

Make stuff editable

When users add data, be it a folder, a task or something else, they often do little mistakes. So the user should always be able to change something that he has created.

Ask before deleting 

People might click on the wrong button. Imagine someone wants to edit a task, but by mistake clicks on the delete button. Shit. Now the task is deleted forever. There are two ways we can avoid this frustration.

First, we always should ask people if they are sure they want to delete something before we delete it.

Second, instead of deleting the elements right away, we could put them in a "trash bin" for a month. So if our user is extra dumb, and clicks by mistake on the alert message that asks for confirmation before deleting something, he might still go back to the "trash bin" to find the task that he deleted by mistake.