As a Brit, the birthday card example feels oddly American. The effect seems plausible, but the UK equivalent slight would be something much more informal
On the other hand, I can understand feeling slighted if the manager consistently recognizes their employees' birthdays but overlooks mine.
When I've seen people feel slighted in the workplace, it's usually due to uneven praise or criticism, or discriminatory stuff like passing over all the black workers with years of experience to promote the one white guy who's been there for 6 months.