If you think you’re foolish or a failure and start looking for proof, you’ll definitely find it. Even if you’ve done something wrong, remember this hadith:
None of you should say: "My soul has become evil," but he should say: "My soul has become remorseless.
— Al-Bukhari Sahih 6180; Al-Adab al-Mufrad 810; Muslim 2251
On the other hand, if you believe you’re a good person and look for evidence to support it, you’ll find that too.
That’s why it’s important to focus on your good traits, recognize them, and keep working to improve yourself.