PADI cards. It always takes months for me to receive them.
1/ OW: our instructor clearly didn't do his job of filling our class in time. It took us more than one month of emailing, contacting him through Facebook, etc. Before finally receiving the PADI temporary card email (it took calling the diveshop to have our files sent to PADI. We should have started with that...). Then, more than a month after that, I received an email from PADI saying that my card was returned to them and to confirm my address. Address that was correct... One more month, and I finally received my card.
2/ AOW: I don't know why, in this time of internet and quick communication, our instructor decided to send our paper file by mail to PADI, instead of doing everything online (and I know they have internet at the resort, we did exchange emails with him before going there, and stayed at that resort). So again, it took ages. This time, I don't know why, I never received any confirmation email from PADI, so it had me worried that my file had been lost into the post (my buddy did receive emails, etc.). Finally, approx. 2 weeks after my buddy and a couple of months after my course, my card finally appeared in the mail.
3/ A bunch of specialties: this time, I was pretty fed up, and paid the express fees myself to make sure I received my cards without any mishaps. It still took approximately a month to receive them, but at least, that was much quicker than previously.
My curse clearly lays with PADI cards only. Last courses were done with a TDI instructor. The next morning, I had received the email for my ecards and two weeks later my cards arrived in my mailbox.
I am currently doing my rescue course, through PADI. I have received notification that they have sent me my EFR card. Good move on the part of my instructor, he is having it sent to the dive shop (for once, I'm doing the course locally). I didn't even know it was possible, and I am hopping that this will be enough to break the curse. Fingers crossed.