#6: Free food

Teachers will not turn down an opportunity to eat free food. It doesn't even matter what it is, really. If it's free, they'll scarf it. Studies have shown that a plate of brownies left in the teacher workroom will be completely consumed in 11.2 minutes on average. That average takes a sharp drop to 5.6 minutes if the brownies are warm and/or freshly baked. If you have a bunch of leftovers in your fridge, particularly after a party or a holiday weekend, and you want to get rid of them, just put them in your child's backpack before school. You'll make a lot of teacher friends, and the teachers will probably wash your Tupperware for you.
Master teachers have a sixth sense for locating free food in the building. If a plate of brownies is placed in the workroom at the southeast end of the building, it will take 3 seconds for a master teacher in the northwest end of the building to detect their presence and only about 10 seconds for her to sprint to the workroom and eat a brownie without anyone knowing that she has just blown her diet (hungry teachers can be quite stealthy).
Some teachers don't have any scruples about taking food from colleagues. I have had teachers take many snacks--most commonly almonds and popcorn--out of my hands on several occasions. A word to the wise: if you pop a bag of popcorn in the workroom, all the teachers in the building will know. They will follow the scent to your room and stick their germy, been-too-busy-to-Purell-this-morning mitts in your popcorn, and help themselves to as much as they want. It's probably best to just go ahead and give them the bag at this point. It was your fault for not locking the door.

#5: Smiley Faces

Every child who has ever played a make-believe game of "school" would tell you that grading papers is awesome. Older elementary students love to trade papers and grade their desk neighbors' work (using a red pen, of course). For those young people who aspire to be teachers, grading papers is just the greatest thing. The reality, of course, is that grading papers is tedious. Those stacks of papers just pile higher and higher until the thought of actually getting through all of them is just overwhelming. Which is why teachers love the smiley face. Smiley faces are easy to draw and can be interpreted many different ways. How do you say, "Nice effort, but your work on this paper just proves my suspicion that you weren't listening to a thing I said yesterday"? Just draw a smiley face. Want to say "This isn't your best work, but you're so darn cute that I just can't bear to give you a bad grade"? Smiley face.
Smiley faces are like snowflakes: no two smileys are alike. Some teachers draw dots for eyes, others draw vertical lines. Some smileys have noses, and some don't. Some smiley faces are enclosed in a circle, and others are not.
Master teachers can draw an entire smiley face--two eyes, a smile, and a circle around it all--without ever picking up the pen or marker from the paper. If you are a teacher and you are not aspiring to this level of smiley face-ness, you need to reevaluate your goals and perhaps spend some time working on this.