Describe a time when you forgot something important

I'd like to talk about the time I forgot my mother's birthday, which still makes me embarrassed to remember. It was about two years ago. I was living in another city, working long hours, and I was completely focused on a big project that was due that week.

The birthday fell on a Thursday. I woke up as usual, rushed to the office and spent the whole morning in meetings. At about two in the afternoon, my sister sent me a short message asking if I was going to call Mum that evening. I read it twice before I understood what she meant. Then I realised, with a jolt, that it was my mother's birthday, and I hadn't bought a gift, sent flowers or even sent a message. It had completely slipped my mind.

I immediately called my mother, apologised and explained that I had been snowed under with work. She was very gracious and said it was fine, but I could hear that she was a little hurt. After work, I ordered a bouquet and a cake to be delivered to her house that same evening, and I stayed on a video call with her and my sister for almost two hours. I also promised to take her out to dinner on my next visit, which I did.

I felt terrible, because she's always remembered mine. It made me realise that being busy isn't an excuse for forgetting the people who matter. Now I put all family birthdays in my phone calendar, with two reminders each, one a week before and one on the day.