It's hard to apologize. Pride gets in the way. What if you weren't really that wrong? But if you were?
Life is short. Apologize. Move on. Share an ice cream. Love each other.
Or do like Charlie the Beagle here. He stole his human's stuffed toy. She was furious. He realized it, felt guilty and did his best to make up for it. It's a good reminder that an apology can take many forms.