Visa Stamping from Canada/ Mexico

This forum has been hugely helpful, so am giving back...
I won't go into the details that others have covered, but here are areas where my experience may be unique and therefore helpful:
1. Like an idiot, I filled out the DS-160 for Toronto and paid my fees before realizing that there were no appointments in Toronto. There doesn't seem to be a lot of info on how to solve this, so I called the helpline. They instructed that I fill out a new DS-160 (the payment receipt is person-specific so carries over to other consulates / DS-160s, but the DS-160 is consulate specific so if you change consulates you have to fill out a new one). If I had to do it over again, I'd start the DS-160 to generate a number, and then use that number to look for appointments before returning to finish the DS-160 and commit to a consulate.
2. Finally went for my appointment to Ottawa on Tuesday 4/25. The embassy people are super, very helpful and professional. Some of the scary stories one hears are probably because people aren't meticulously doing their homework. I saw a family get turned away by security because they came with a massive backpack (clearly not allowed, as stated on the embassy website). Security assured them they could come back before 11 am, even if they missed their original appointment time. the mother asked if she could sit inside with her baby while the husband returned to the hotel to drop off the backpack, and the security guy agreed, as long as she had all her documents. I saw her get turned away again inside, because she was missing some documents. In these cases, what do you expect.
3. The visa process for me was super easy, no real questions asked, and the lady was super nice. I work in finance and have degrees from the US, if that helps, since people on this forum are often curious about candidate profile. Here's where I had a hiccup--apparently their system still had me registered as a student (even though I haven't been a student in years, and have other visas since...makes no sense), and they couldn't issue the visa until the system first cleared that, which takes 1-2 days. I freaked out a bit but she assured me its a common glitch, and apologized.
4. My status update said "Administrative Processing", and even though other posts have mentioned that it is normal, it is kind of unnerving, since you can't really tell whether your "Admin Processing" status is the normal placeholder, or whether you really are in admin processing. The scary explanation on the status popup about how admin processing can take weeks, doesn't really reassure. However, I did some reading around this and found that only 2% of cases get kicked into actual admin processing, and there are very specific categories for this--security threat (including the handling of sensitive data, which is why it seems to happen to IT folks more than others), coming up on a background check screen (which can be annoying if you have a common name), etc. It really doesn't seem like a matter of random chance, as some other posters would have you believe.
5. Status changed to issued on Friday morning, after 3 looooong days. I was stuck there for the weekend, but so, so relieved...even though the consulate had assured me I'd get my passport back in 5 days in my case, these things are always unnerving.
6. I opted to have Canada Post deliver my passport to my hotel since I had moved to another city by then. This was a slightly risky proposition, in retrospect. Canada Post doesn't deliver weekends, and doesn't seem to have the greatest track record in general, if you google about them in a fit of paranoia, as I did. Also, there's a risk that the hotel botch up the signing of the parcel...sounds paranoid, but when your passport flashes before your eyes, you do wish you had taken the safest possible option, which is to pick up in person.
Anyway, I received my passport without any hiccups, and other than the extra 2 days spent waiting for the system to clear my student status, this was an incredibly smooth process. Hope this helps.