In the morning rush hour a bus will come and it will be too crowded. Just wait for the next one. I often wait through at least one, usually 2, sometimes 3 or 4 buses, until I find "the right one" - which is to say, the one with as few people as possible. How do you know if there's too many people on a bus? If people are standing, there's no f'ing way I'm getting on that bus. If it looks like I might have to sit right next to someone, I'm going to reconsider getting on it. If there's lots of open space - usually toward the rear, but I like to see a few regular seats open, too - then I feel pretty comfortable getting on it. As a rule, express buses are typically more crowded than locals.
2. The Grocery Store
At certain grocery stores there's a "self-checkout" line. You'd think I'd be a fan of this, but I'm not. If you buy produce or alcohol you will find that you will probably have to deal with someone, which negates the purpose of having these things, right? It's best just to figure out which clerk is not going to talk to you and head for that one. Find a sullen teenager - someone who looks like they read either manga or classic literature - and go for that one. Avoid grown-ups who look kind of happy and well adjusted, as they will probably ask you questions about your weekend.
3. The Office Bathroom
There's 2 choices if someone is using the bathroom at the same time: you can either enter a war of attrition with them or you can act as quickly as possible, because you are not going to look at another person in the bathroom. The fight option becomes more difficult if you were there first, because the other person will (incorrectly) assume you are going to leave first and wait for you to do so.
In this case, or if (heaven forbid) a third person enters when you have chosen "fight", you have to dig in your heels. Check your email on your phone or read about Scott Baio's latest public gaffe in Entertainment Weekly. Check the size of your pants and consider if you should buy a different size the next time you purchase pants. You are not going to leave that bathroom until the coast is perfectly clear.
In a corporate setting, there's often a neglected or under-utilized bathroom. Find this in your building and the world is yours.
4. Elevators
I work in a building with some elevator work being done on it, so the half-broken call buttons serve me pretty well. When I call for an elevator, usually one will show up with some people on it, but if I wait for another, it will be empty. By waiting an extra 10 seconds, I can spend the next 45 seconds alone or pretty much alone instead of crowded into a small space with some people.
If you work in a building with normal, functioning elevators - and a bank of elevators, not just one or two - you will have to call for an elevator, go grab a Diet Coke, then - after the first one has come - get another one and actually get on this one. Or you could experiment to see how many times it takes to get an elevator that's actually acceptable. I'd recommend this as a long term strategy, but do remember that it's going to vary by the time of day. If you leave work early or late, it's probably not worth it, but if you leave between 4:45 and 5:30, then you should try it out.
If the elevator ride is short enough, it is probably worth just taking the damn escalator. However, if you suspect there are people you are with that would be ticked off by bothering to take the elevator, then I would suggest taking the elevator. When the choices you have make your inconvenience a wash either way, you should always make sure to maximize the discomfort of others - that's what passive aggression is all about.
5. General Office Behavior
One way to bother people is to take the paper out of the printer. It's a small thing, but when the print jobs stack up, it can be a real pain the ass. There's usually a stapler there, too, so just take out all the staples and put the replacement staple cartridges in the back of the supply closet.
6. Social Graces
When shaking someone's hand, do so with an incredibly limp hand or use your left hand. If they really want to shake hands, then let them. Touching people is a gross and stupid gesture to begin with.
7. Domestic Living
If you live with someone and have TiVo, the most passive-aggressive thing you can do - outside of throwing out all their stuff while they are at work - is cancel everything they ask it to record. The best way to do this without getting caught in the act is using Tivo Central.
