the pleasure of finding things out

is an excellent book by Richard Feynman (isbn 978-0-141-03143-9). As usual I'm going to quote from a few pages:
Looking at the bird he says, "Do you know what that bird is? It's a brown throated thrush; but in Portuguese it's a … in Italian a …, " he says "in Chinese it's a …, in Japanese a …," etcetera. "Now," he says, "you know in all the languages you want to know what the name of the bird is and when you've finished with all that," he says, "you'll know absolutely nothing whatever about the bird. You only know about humans in different places and what they call the bird. Now," he says, "let's look at the bird."
I said, "Say, Pop, I noticed something: When I pull the wagon the ball rolls to the back of the wagon, and when I'm pulling it along and I suddenly stop, the ball rolls to the front of the wagon," and I says, "why is that?" And he said, "That nobody knows," he said. "The general principe is that things that are moving try to keep on moving and things that are standing still tend to stand still unless you push on them hard." And he says, "This tendency is called inertia but nobody knows why it's true." Now that's a deep understanding - he doesn't give me a name, he knew the difference between knowing the name of something and knowing something, which I learnt very early.
To do high, real good physics work you do need absolutely solid lengths of time.
You cannot expected old designs to work in new circumstances.
If you are in a hurry, you must dissipate heat.
We had lots of fun.
The people underneath didn't know at all what they were doing. And the Army wanted to keep it that way; there was no information going back and forth... I felt that you couldn't make the plant safe unless you knew how it worked… I said that the first thing there has to be is that the technical guys know what we're doing. Oppenheimer went and talked to the security people and got special permission. So I had a nice lecture in which I told them what we were doing, and they were all excited. We're fighting a war. We see what it is. They knew what the numbers meant. If the pressure came out higher, that meant there was more energy released and so on and so on. They knew what they were doing. Complete transformation! They began to invent ways of doing it better. They supervised the scheme. They worked all night. They didn't need supervising at night. They didn't need anything. They understood everything. They invented several of the programs that we used and so forth. So my boys really came through and all that had to be done was to tell them what it was, that's all. It's just, don't tell them they're punching holes. As a result, although it took them nine months to do three problems before, we did nine problems in three months.
Most of the trouble was the big shots coming all the time and saying you're going to break something, going to break something.
We used to go for walks often to get rest.
Advertising, for example, is an example of a scientifically immoral description of the products.
The magnetic properties on a very small scale are not the same as on a large scale.
But what we ought to be able to do seems gigantic compared with our confused accomplishments. Why is this? Why can't we conquer ourselves?
Erosion and blow-by are not what the design expected. They are warnings that something is wrong. The equipment is not operating as expected, and therefore there is a danger that it can operate with even wider deviations in this unexpected and not thoroughly understood way… The O-rings of the Solid Booster Rockets were not designed to erode. Erosion was a clue that something was wrong. Erosion was not something from which safety can be inferred.
We have also found that certification criteria used in Flight Readiness Reviews often develop a gradually decreasing strictness.
The computer software checking system and attitude is of highest quality. There appears to be no process of gradually fooling oneself while degrading standards so characteristic of the Solid Rocket Booster or Space Shuttle Main Engine safety systems. To be sure, there have been recent suggestions by management to curtail such elaborate and expensive tests as being unnecessary at this late date in Shuttle history. This must be resisted for it does not appreciate the mutual subtle influences, and sources of error generated by even small changes of one part of a program on another. There are perpetual requests for changes as new payloads and new demands and modifications are suggested by the users. Changes are expensive because they require extensive testing. The proper way to save money is to curtail the number of requested changes, not the quality of testing for each.
Official management, on the other hand, claims to believe the probability of failure is a thousand times less. One reason for this may be an attempt to assure the government of NASA perfection and success in order to ensure the supply of funds. The other may be that they sincerely believe it to be true, indicating an almost incredible lack of communication between themselves and their working engineers.
It is presumptuous if one says, "We're going to find the ultimate particle, or the unified field laws," or "the" anything.