Why is my dad so angry (Leo/Virgo cusp)?

He has some Virgo, so I figured he'd be more mild.. but i've never met someone so angry, cocky, or egotistical in my life. It seems like he finds reasons not to trust people and yell at them. He yells at people at stores all the time for little mistakes and it's really embarrassing.. he nags me and my siblings, he rants about loyalty all the time.. saying how my mom screwed him over. He's so negative and serious, yet explosive. I thought Leos were playful and confident.. My dad is a good father though. He provides for us and wants us to do well in life, he's just emotionally damaging. I know his moon sign is Gemini and his rising is Pisces.