The speaks to your inexperience making applications - using anecdotes and assumptions about "the average user" to determine what to do is nowhere near as useful as asking your actual users. Real data is better than guesswork.
That's true for the users you've seen. My users all open emails with no problem.
Now do you see why "the average user" isn't useful to determine how to build something? Even if most people suck at using email, in my app it works well.