Speaking about batteries, yes, carry spare batteries. But also remember to check their charge status. A friend of mine at work decided to do some night shots up in the mountains, about 20-40 minute drive from where he lived, only to get their and find out his batteries were almost empty and didn't have spares. I'm sure he hasn't ever made this mistake again.
I usually carry about 3-4 spare (sets) batteries in my bag. I'm too paranoid about this and making sure I have enough memory cards.
D Pentney wrote:So.. this so far, is really just about being prepared, and it seems that every now and then we're all caught out with something!
And yes, this is about being prepared and making sure you have at least a mental check list of what you need to do before you forget something. This thread hopefully will also allow us to make anecdotes from our experiences and share a few laughs

After all, we are supposed to be a friendly community.
Which just reminds me of another personal fail (which turned out well in the end).
This happened a few years ago, I became extremely busy at work that I had to hold off on taking out my camera for some photo trips that my gear was just sitting at home doing nothing. At the time I had a Sigma 70-200 f2.8 lens and during some wet climate season I left it sitting near a humid spot in my room. Moisture started gathering inside the front element of the lens after a couple of months and I had to send it back to get it cleaned. I was sure it would cost me a fortune to have it serviced, even under warranty. Luckily Sigma just serviced it for free and since then I have always kept my gear properly stored away when not in use.
That is of course until sometime early this year when I accidentally dropped my D700 + Nikkor 70-200 (sold my Sigma and switched) breaking the protective filter in front of the lens, having the shards of that filter scratch the front element of the lens, having the flash hot-shoe mount on the D700 get bent and cost me around $1000 for repairs. A very expensive lesson indeed.
Of course this wasn't the first time I had an accident and dropped my camera. My first accident was while on my bike with my first D90 + Sigma 18-50 lens around my shoulder, swerving to avoid a bus, falling of my bike only to see the D90 get run over. Luckily the lens survived with only minor scratches on the exterior, the D90 wasn't that lucky however.