Rule 38: Since poker is a game of positioning oneself to win (but with no guarantee of winning), there are going to be times when doing exactly

Since poker is a game of positioning oneself to win (but with no guarantee of winning), there are going to be times when doing exactly the right thing leads to losses.
There aren't many sports or games where you can have a lifetime of experience, make every play exactly right, and lose. But poker is one of them. This tells us something it tells us not to approach it like other games.
This is a difficult concept for some players to understand. They ask. «What am I doing wrong?» And if the answer is «Nothing», it leaves no rational explanation. Yet this situation is common in poker. Coolness must prevail. Clinical detachment and composure need to be embraced.

Rule 37: It's a mistake to use experience alone to determine what good poker play is.

Long-time experience can be deceptive. Our memory can be selective. It can mislead us, overemphasizing some things that occurred and underemphasizing others. A big win may shine brightly in our memory, yet if looked at closer, it might not be backed up by good play. Always make sure you are playing right first, and then get a lot of experience at it.
Don't do it in reverse. Don't reference your many years of experience
as proof that you mast be playing right. This kind of self-referential
argument is capable of containing numerous errors.
Similar card situations occur again and again, thousands of times. And some players have been playing them wrong – for years. Worse, such a player often learns to do so expertly! In fact, many of them become
excellent players, amazingly adept at «working around» their own flaws and weaknesses. They become experts at starting out with their own self-
imposed handicaps and overcoming them. They are like track stars who
become very proficient at finding ever newer and more innovative ways to
get over the hurdles that they themselves have put in their own way.

Rule 36: One of the main ways we improve in the game of poker is by getting certain lessons pounded into our heads.

Books, seminars, and other kinds of advice are all well and good, but
nothing instructs us in certain lessons like experience. Lessons learned
through painful experience tend to form a deep groove in the brain.

«You can close your eyes to reality, but not to memory». – Stanislaw J. Lec

Free rules for poker 35: If you're doing a lot of folding, won't this look odd to the other players?

You might sometimes get the feeling that all this folding you're doing looks
pretty obvious to the other players. You can almost feel their watchful eyes
on you – and hear them thinking: «Boy, he sure plays tight. He must be
waiting for the perfect hand to come along».
If you took a survey, though, you would find this is not what most low-
level opponents are thinking at all. Here is what they are really thinking
when you are doing a lot of folding:

1. Nothing.
2. You're a player who must be getting pretty lousy cards.
3. Great “you're out of the way“ let the action commence without
you.
4. They really don't care (or even notice). Frankly, there are enough
other opponents in the game to worry about, and the fewer
opponents, the better.
5. You must be a fairly «tight» player may be a «rock».

Notice that the thing you were most worried about came in last –
which it probably would in a real survey.

Free rules for poker 34: In the best players there is a streak of simple common sense.

If we put things in these terms, the game seems pretty simple.
Strategies are somewhat different than this at higher, more sophisticated
levels of play, of course, but for most players this common sense aspect is
something to keep in mind. It is possible for a player to get lost in
convoluted scheming and overlook this simple truth – that a good portion of
the game is simply common sense. And this trait is also present in the great
players. In fact, the vast majority of plays in the game of poker are not
fancy, sophisticated plays, but obvious ones. But these have to be done right
too.

Free rules for poker 33: Don't go on the offense against a large field of players with a weak hand.

Here's a poker secret: When you don't have good cards, someone else
usually does. Don't go into the aggressive/offense mode in a situation where
you're weak and they are a mystery. Remember, the good cards have to be
somewhere.

Free rules for poker 32: You may as well bet if you intend to call.

It is a generally accepted idea that if your hand is good enough to call a bet with, then you are better off betting. (And this is a situation that occurs very often in poker.) The thinking is that if you're going to call a bet, you might as well be the one driving the betting. It's going to cost the same amount anyway at least this way you're in the driver's seat. There is an intimidation aspect that also accrues from doing this whether in the individual hand, or cumulatively, over many hands a general aura of aggressiveness.