Not sure if it's not meant to be humorous - at least it uses (and reverses) several well-known tropes:
- "we said no gifts" - right... so you're the only one who actually followed that? Well, bad luck!
- usually it's the husband forgetting the wife's birthday, not the other way around.
- ...and finally, I'd like to quote Jesus himself: "He who is without sin can cast the first stone" - this ad (and the others) show situations most of us have been in, so they're at least relatable.
The birthday one was in no way meant to be humorous.