Hmm this might sound controversial but I don't think birthdays are important at all. Of course, I do appreciate that people celebrate this special day for me. But given these two scenarios: (a) a friend who is there for you almost the entire year but forgot about your birthday vs (b) a friend who only appears during your birthday but missing in action for the most parts of the year.. I would gladly pick the first friend.

So I have no issues if people forgot about my birthday. How they treat me for the rest of the 364 days in the year are important too, if not equally important.