I was so late that I missed dinner.
What happened and why did you miss dinner?
I had to show something to someone.
It is good to let people know you are running late if it might disrupt or delay an event. It is basic decency to tell the other parties involved.
I'm sorry I ruined the plans, my bad.
It's okay and as long as you don't do it again and you know that what you did was wrong, then you are forgiven. You should strive to go home and to arrive on any plans you have on time so that people who count on you do not get their feelings hurt with your commitments, and I hope you be in time in the future.