Ok. I read somewhere that it is sometimes Hashem’s hand if we miss an appointment. Is this true if a person misses it because they overslept, or would that be the person’s fault for not getting enough sleep or not setting an alarm? Also, is a person’s tefillah less likely to be granted if they are impatient or lack confidence it will be granted?

Shalom, If someone is negligent then they cannot blame God for the bad outcome of their actions. Rather they should learn why things went wrong and not repeat their own mistakes, Kol Tuv