Nobody likes a complainer.
I have been trying for three days to work up to teaching you the difficult lesson of how to be a likeable complainer. Everyone likes a complainer actually, as long as it is done properly. And so...
1. Employ the rule of five: for every five complaints, one is casually mentioned, one is kept to oneself, one is for your familiars, one is made light of, and one is turned into something else completely.
2. Be enthusiastic about strange, tiny things to keep everyone off balance. If you're frequently excited about the endangered lichen Yellow Specklebelly, your fury about how people inefficiently pack boxes of books (it's not rocket science!) will fit more naturally into a range of mild eccentricities.
3. Use these complaint moderating tools:
A. Humor ("You have filled this box and yet there's so much space I can fit my right foot in. I can take my right foot out. I can put my right foot in, and I can shake it all about.")
B. Science ("Ah, see, through the use of stacking like sized objects the actual mass of the box is increased! Get me a grant. I feel a study coming on to try to prove St + F^2 = M(12). Why, solving the inefficiencies of box packing is just like rocket science!")
C. Appeal to the greater good ("By packing this box with stacking we can use 80% fewer boxes saving the library 62 work hours per annum.")
4. Complain in a crowd. Like so many things that can get lost in a crowd (a comment, a child, a hat, common sense) complaining barely registers as complaining when it's done with a group. That little knot of workers you see gathered at a restaurant, a store, the library, are they figuring out how to deal with a problem? Maybe. Are they enjoying some pleasant socializing? Maybe. Are they complaining bitterly about a wide range of petty issues so that the burden of solitary complaining is shared out amongst them and lightened? Oh yes.
5. There is no sense in putting lipstick on a pig, but complaining is not nearly as attractive (or, alas, tasty) as a pig and can benefit from any amount of gussying up that you can manage. Joking, science, and being constructive are, of course, all just a variety of frocks, butterfly facepainting, vintage jewelry, perfumes, and spray on tans. But don't stop there. Every device, trick, and talent that humanity is heir to can be piled onto one's complaining. Augment your complaining with analysis, wisdom, insight, coolness, storytelling, fantasy, wit, and perception, and, before you know it, people may not even recognize the complaining underneath it all. Hell, you might not recognize the complaining buried in all your add-ons. Indeed, there might not even be any complaining underneath all of that anymore.