Jackie's biggest faux pas was that she promised a cake and didn't deliver. That's just mean.
As for the flavor of the cake, my feeling is that if you can't have your favorite flavor cake on your birthday, when exactly can you have it?
If you are celebrating your birthday with family and friends, aren't these the same people you'd likely be sharing all your cakes with? That person with the strawberry allergy, that person who doesn't like chocolate--how often are you going to have the choice of the cake flavor when they aren't around to eat it?
I suppose you could bake/buy a cake just for yourself, but most cakes are pretty large for one person to eat.
In fact, because I live alone, pretty much the only time I get cake is at someone else's celebration--when I'm eating their favorite flavor cake--or on my birthday, where you can be sure that if I have any say in the cake, it will be chocolate with buttercream frosting. If someone surprises me with a cake that isn't chocolate, I'll be grateful, but not as happy as I would be if the cake were chocolate. As for example, last year, when my sister kindly gave me a cake--an orange-flavored cake, because she doesn't like chocolate cake. It was a very nice cake, but it didn't feel like my birthday cake, because it wasn't chocolate. Not that Sis will ever hear that from me, of course.