I am by no means an expert, but here are a couple of options that come to mind. I came up with most of these by thinking "what kind of emergency are you reasonably likely to run into at some point, and what can you do to mitigate them?"
Learn some measure of first aid, or at least the Heimlich maneuver and CPR.
Keep a Seat belt cutter and window breaker in your glove compartment. And on the subject, there are a bunch of other things that you may want to keep in your car as well.
Have an emergency kit at home, and have a plan for dealing with natural disasters (fire, storms, etc). If you live with anyone, make sure that everyone is on the same page about this.
On the financial side, have an emergency fund. This might not impress your friends, but given how likely financial emergencies (e.g. unexpectedly losing a job) are relative to other emergencies, this is a good thing to plan for nonetheless. I think the standard advice is to have something on the order 3-6 months of income tucked away for a rainy day.
Keep a Seat belt cutter and window breaker in your glove compartment.
I would like to see some data on whether they are useful, that is, how likely are you to find yourself in a situation where having them in your glove compartment will be important.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.