Is screaming at one's mother sometimes—without intending to harm her—considered among the major sins that warrant the angels' curse, and is thinking about a non-mahram person forbidden in Sharia even if there is no contact with them?

Praise be to Allah who has enabled you to repent from neglecting prayer and acts of worship. And your shouting at your mother is forbidden. You must repent, show dutifulness to her, and not raise your voice at her. If the shouting is due to an illness beyond your control, there is no sin upon you, but you must seek treatment. Love (passion) is a disease that corrupts the heart and distances one from Allah. There is no sin upon you for what enters your heart as long as you do not cause it through something unlawful. You should strive to rid yourself of it and guard your thoughts.