Does you sometimes not receive a notification that you received a message on Facebook?

[Maggie]

I sometimes don't receive a notification that i have a message from someone. Then when I click on the messages between me and the person, it will say that I received a message from them, but I never received a notification. Does this ever happen to you, and is there any ways to prevent it?

[August]

If I comment on a profile comment or picture comment. If someone likes my comment, I get another notification. If I like I a comment or a picture, I don't get any notifications. notifications can be extremely annoying.