I've lost friends over 10 minutes. I have deadlines and their selfishness is aggravating. Just talking about this bends me out of shape.
It bends me out of shape too but in the opposite direction. Good for whomever you lost. I could never be friends with anyone that uptight.
None of my friends are always on time. It's just assumed in gatherings that someone will be 10 minutes late. Sometimes it's me. Sometimes it's not me. Sometimes it's actually all of us. It's never a big deal.