Running is a pretty simple activity, right? All you need is a pair of shoes and a place to stride. Well, you technically don't *need* shoes (see Abebe Bikila), but you get the point.
That being said, there are some running faux pas about which you may not know, or some gray areas to which you don't know the answers. Don't fret, my running homies. I'm here to set you straight on some things that are good, and others that are not good to do while burning off that Triple Cheeseburger from Dinkers.
Legal-ish disclaimer: I don't have much of a filter. These are also just my opinions. If you like being wrong, you're welcome to disagree with them. You've been warned.
Snot rockets
You know, the good ol' fashioned "farmer's blow". Totally ok to do. But, there's a right way to do it. Frankly, it's pretty much common sense here. Make sure no one is in the line of fire. Make sure you're outside. Blah, blah, blah. Runner's World has a pretty good instructional video on how to execute the snot rocket. Is it gross? Eh, I guess. But running with cleared nose holes will be so much more comfortable and will change your running life.
Waving at other people
If you don't acknowledge another human you pass on a run, then you're probably a sociopath (maybe not, but we're playing the odds) . It doesn't matter if it's someone's walking, running, biking, hell, even driving, give them a wave, smile or nod. Acknowledge their presence; they're a human too.
Tailing another runner
You're out for a run, you see another runner (maybe they're passing you, maybe they're going the opposite direction, whatevs) and they're going a little faster than you. So you decide to latch on to their pace at a pretty close distance. Please don't do this. Not only is this creepy, but it's just not cool to use them as your pacer.
Racing another runner
Same as above - you see another runner and start to "race" them. Again, don't do this. It just makes you look like a dick.
Passing someone on a sidewalk or trail
You may be crushing a tempo workout and feeling the flow. So you may naturally need to run around someone on the sidewalk or trail that you're using. No biggie. However, don't scare the shit out of them when you blast past them at breakneck speed. Announce yourself. It can be something as simple as the usual "passing on the left" (you should always try to pass on the left). Don't have the breath to say that? Don't sweat it. Just make some kind of audible noise so that the person knows you're there - cough, spit, grunt, snot rocket...something.
Farting
As long as you're not going to poo yourself, just let it fly. We all do it, so who cares? If you're running with someone and they're behind you, just give them a heads up. Unless you don't like them. Then let 'er rip and let's hope you ate onions.
So those are a few of my etiquette rules. What are your tips? Feel free to comment or add to this list, or tell me I'm gross, or full of crap. Whatever.