Over the years, I've come to learn that excuses are a basic human response to changes in our situation. When something happens that we're not expecting, we make excuses. That exam you failed? That business opportunity you lost? That divorce? But it's worth noting that excuses only make us seem weak and immature. Making excuses is the equivalent of blaming someone for our mistakes.
The only way to gain experience is to own up to our mistakes and accept our flaws. Making it a habit is unhealthy.