In OPs defense though, I understand the use of best friend in her case, though I don't think she fully understands it. See, I have someone I consider to be my best friend, but she has a different best friend. She's called me akin to a sister, but never a best friend (that I'm aware of). Just because someone considers you a best friend, doesn't mean you have to see them the same way. So OP may see this other girl has her BF but the other girl may not see it that way.

Maybe because they knew you had to work and they thought they would see you there anyway?

I'd say your friend knew that you worked there at that time so they went there as a surprise for you.

They better of tipped you. There are so many birthday guests that feel they are above tipping the waiter on their birthdays.

If OP's BF was any kind of friend at all, they'd at least have extended an invite. "Hey, I realize you probably have to work, but if there's any way you can get off, we're having my birthday dinner such-and-so night." Or, if this was a last-minute impromptu dinner, BF could have showed up to the restaurant and explained to OP, "We just decided to grab dinner, and I know you work here, so I thought we'd come here and you can still be a part of it." Totally acceptable. But if BF just showed up with a horde of friends and was just like "yeah I'll have a diet Coke" to OP... then I think that's a pretty bitch move.

Obliviously you're working so he or she knew you were busy.

Maybe they didn't invite you because they knew u where going to be there... Or they hate u

that sucks.. maybe find friends that appreiacte u better

Blow out the candles before she has a chance to

maybe they knew you were worming got and that's why they went to your job in the first place. try to look at the positive things in life.