Angels, as a general rule, cause more harm than good.
Bananas (unlike pears) are good; always bring one to parties.
Count the shadows.
Evil comes in many degrees and packages.
Feel down? Don't use a "Bliss" patch.
Go for the eye(stalks).
Hospitals are bad; avoid whenever possible.
If you're confused about something, don't be afraid to ask questions; fear the answers.
Just smile and nod if the Doctor asks you something you don't understand.
Killing is not (always) the answer.
Life is an adventure, a challenge, a game, and a Hitchhiker's Guide to the Galaxy reference.
Mysteries are made to be solved; dive in headfirst!
Never trust a cat, nun, nurse, or combination of the three.
Options exist for everything, just be sure to take the best one.
Place your faith in only complete strangers and those you can trust.
Quit while you're ahead; it'll all be downhill from here on in.
Safety is important, but only if the reward for losing it is less so.
The water on Mars is not fit for consumption; no touchy!
Upgrades are bad.
Villains are, more often than not, misunderstood megalomaniacs who just need a hug. Right...
When the Doctor tells you to shut up and run, it's probably in your best interest to do so.
X words are overrated, like gravity.
Yes should be your answer to everything (except the "no"'s).
Zebra stampedes on the moon are more likely to kill you than a Dalek if you just keep talking to it.