It is surprisingly easy in a squabble to think that you were not wrong. I think we all like to think highly of ourselves. But as humans there's a cause and effect factor - your behavior influences my actions and vice versa. No one squabbles with themselves, and if we are squabbling we are raising our voices, and thinking about how to win. We are not being kind or loving in that instance. So even though your part in the squabble may be minuscule, you played a part and both of you ought to apologize so that restoration can take place.
Dagwood and Herbert are lifelong friends, so I'm sure after many attempts at restoration they figured out that dual apologies were in order. In our lifelong friendships and relationships, there's a lot at stake when we both can't say "I'm sorry" with sincerity. Sometimes the one who apologizes first is the one who recognizes their offense, or sometimes they're just trying to be the bigger person, recognizing what's at stake. Either way, it requires a degree of humility to apologize but our relationships are worth it. Let's not let small squabbles turn into generational rifts.
Let nothing be done through strife or vainglory, but in lowliness of mind let each esteem other better than themselves. Philippians 2:3 [KJV]
Is it easier or more difficult to forgive those that you have a close relationship with? Do you always feel you're right in a squabble? Is it possible you're not?