Why do most habit apps fail after the first week?

I've been building Leo: 21 Day Habit Builder, and while working on it I kept asking myself why I abandoned almost every habit app I'd tried.

For me, it wasn't because they lacked features it was because they had too many.

I'd start with 8–10 habits, feel motivated for a few days, then completely stop.

That led me to build Leo around one simple idea:

One goal. One focus. 21 days.

Instead of tracking everything, the app encourages you to commit to just one meaningful challenge until it becomes a habit.

I'm curious whether other people have had the same experience.

• What usually makes you stop using a habit tracker?

• Is it too much setup, too many reminders, or simply losing motivation?

• If you could remove one thing from today's habit apps, what would it be?

I'd love to learn from your experiences and use the feedback to improve Leo before the next update.