YOUR DOING IT WRONG

Congratulations, there are only (infinity - epsilon) ways of screwing up remaining.

If you're designing a font...

Make sure that you can spell such words as "ignorance" and "stupid". Knowing the difference between "your" and "you're" is a helpful bonus.

(Oh, this could be a long list)

Don't keep pouring money into a doomed, terrible project just to avoid looking bad (*cough* ID cards *cough*).
Don't think that just because you got voted in you have a mandate from the people to carry out everything on your manifesto. They probably violently disagreed with 50% of your manifesto, compared to 80% for the other party.
I do not want to pay for children to be indoctrinated into any religion, thanks.
Yes, I know people are gullible fools who'll believe anything a man in a nice suit tells them and if you don't take advantage of it someone else will, but really, in the long term we'll be better off if you teach the kids some good cynicism and rationality early in life. That means getting rid of state-sponsored religious indoctrination, and teaching science, logic, etc. Teach them about logical fallacies, psychology, human failings, and let's try and prevent the various kinds of stupidity that have plagued humanity for the last 100 millennia or so.

Don't conduct any "scientific" experiments on your programme until you LEARN SOME FUCKING SCIENCE. In particular, please look up the meanings of "double blind trial" and "sample size".
Think carefully before using the phrase "If this trend continues [insert shocking prediction here]". This can too easily lead to such stupidity as "You've lost 2lb this week - if this trend continues you'll be the right weight by Christmas!". Yeaaahh, if that trend continues, you'll eventually have negative weight, so what?

Don't play the National Lottery. You are almost guaranteed to lose more than you gain. Put it in the bank instead, or if you can't miss out on having bugger all chance of winning a million, then buy premium bonds. (Actually, if you're a higher rate taxpayer, premium bonds might be a good idea anyway; however, this page is supposed to be me whinging, not giving out financial advice).

It should not be possible for the door to slam, ever. It should be very quiet in its operation. Use padding, damping, etc.

For fuck's sake set it to a ringtone that isn't annoying, or even better turn the ringer off.

Please put in the day of the week as well so I don't have to look it up all the time. It also adds in some redundancy in case you got the date wrong.

Firstly, congratulations. However, please do not cut any bits off your new baby, unless it has a specific medical condition that needs fixing. It's really not the way you want to enter the world. And no, I don't care what your religious text says.

Make text labels *legible*. Setting text in the form of slightly raised (or etched) plastic of the same colour as the background DOES NOT COUNT. I am relatively young and have great difficulty reading them; it must be utterly hopeless for anyone older.
Do not use digital where analogue would be better. Eg. car speedometer, kitchen scales, tyre inflator dial. If you are doing it for marketing purposes ("New! Digital! Technology!") rather than just ignorance, then lose even more points.

Please use understandable male/female indicators on the doors. Your abstract symbols may look cool (ok, pretentious), but they do not serve the intended purpose. The standard two-legged/one-legged signs are still abstract, but they are at least standard. Or follow the example of one Copenhagen restaurant and just put pictures of the appropriate genitals on the door, I don't care. Just make it obvious. And the less said about themed Mexican restaurants, the better (hint: female toilets don't have urinals).