Which is harder -- to get shot with a bullet, or to say I'm sorry? Which is harder -- to have a tooth pulled, or to admit publicly that you are wrong? Which is harder -- to break a drug addiction or to forgive someone for a grave offense? These all may be difficult, but that last one is probably the hardest. I cannot count how many people I have met in my lifetime (even Catholics) who say that there is someone that they just cannot ever forgive. I always point out that Jesus tells us that refusal to forgive will damn someone to eternal Hell (cf. Matthew 6:15), but the response of most is something akin to, you don't understand what he did to me. We can call it holding a grudge or harboring resentment or even protecting oneself, but in the end it is a failure to forgive; and that is a grave sin. It may be hard (very hard), but it is necessary. Do not let another day go by without forgiving those (all of them) who have wronged you.