I'm sure they will show up when you feel sad or something and they will bring a smile to your face. Swap packages always show up to make me feel better. I.E. I got two the weekend my grandpa passed away.
It is interesting. My packages do that too! Getting packages always makes me happy. Infact, my mom has a 6th sense about those kinda things and always ends up sending a care package fulla my favorite things just as things get crazy in my life. I don't even have to tell her, she just knows! Like at Valentines, she forgot to mail out my package, then came Easter, so she combined the two, but forgot to send them, then, in the beginning of last month, we had some really awful things happen, and the next day, her package arrives and made things seem a lot better.