I have nowhere near the collection of several of you guys. I got AOW several months after OW when it presented the only way to get out on a boat in N. FL in winter. One of my Adventure Dives was Nitrox. The instructor said I should finish the course back home and did (well, had to do and pay for both halves of the course there). Then I got curious about all the courses in the famous PADI list. I noticed Rescue, and read on SB this was a good idea. So, I took EFR (in New Jersey, as the one here at home was cancelled--try legally parking close to the dive shop in Hoboken.....). After that it was back to the FL panhandle, and I got the idea to do 4 more specialties to get the magic MSD. I actually took 5 within our 3 months there (well I had the $ then). The instructor was ready to collect my $41 fee and send out for my MSD card, but I said to hold off until next week when I will do my 50th dive.....Wanted it to be "official". Man I knew I was no Master Diver, but I had the patch to prove I was. I learned from SB it's probably a huge mistake to wear the cap I put that patch on around divers. So I wore it elsewhere. "You're not really a Master Scuba Diver, are you?" "Why, yes, I am". If I weren't married I can't even imagine how that would've worked with the ladies.
Next, Divemaster. Thought I'd get one more card besides Rescue that really meant something. And it did. More work getting that one than most of the others combined. It was interesting being a student again, after so many years as a Band teacher. And it was fulfilling assisting with courses, where you got back into education--and without the buck stopping with you all the time. And, I did make enough $ in 4 seasons to cover the course, gas and some left over.
No more cards for me. I'm way behind someone like stuartv, but still know way too much for the simpleton diving I do.