This is fact of life, about those who seems nice & kind hearted yet one should avoid their wrath. For some reason they can hold grudge as long as they like, as much as they want, even if you made only silly mistakes.
Common sense dictate that if one can't forgive you for your silly mistakes, expect them to leave you when you do big. For this people, being right is everything, it fuels their pride and ego. They despise people that they feel are not in the same league, that is always do thing correctly according to their mindset.
Ultimately, this people are hard to forgive, and harder to apologise in earnest.
Let's pray for them.