I made this question in StackOverflow (it's now deleted) and just after I posted it, I found a typo that solved my problem and decided delete the question.
In the meantime, someone commented my question trying to help me, then I posted a comment like:
Thank You for your help. It was just a typo. I'll delete the question
I waited 10 minutes before delete the question, hoping that the commenter see my thanks, but then I start to thinking: I was trying be polite, but it's a question without any purpose.
Leave a bad question online is a right thing to do for, since I was trying to be polite, or I just was making noise in the site?