Beginners look at the middle of the table and ask what it gives them. The better question, and it takes two seconds, is what it might be giving somebody else.
Before you put chips in after the flop, run these. They are all answerable from the shared cards alone, without knowing anybody's hand.
Then somebody holding two more of that suit has a flush, and your two pair is in serious trouble. Four of one suit showing is worse still — anyone with a single card of that suit has it.
Then a full house is possible. A pair on the board is also why your own pair is worth less than it looks — see the warning below.
Three cards within a five-rank window means someone can be holding a straight. 9-8-7 on the board is dangerous; K-8-3 is not.
If there is a pair of queens in the middle, every single player still in the hand has a pair of queens. It adds nothing to your hand relative to theirs. What makes your hand yours is only ever what your own two cards contribute — and if the answer is nothing, you are not beating anyone who is still betting.
It is a reason to slow down. A flush being possible does not mean anyone has one. What it should change is how much you are willing to put in: bet smaller, call rather than raise, and be ready to believe someone who suddenly gets very interested.
When a scary card lands and the quiet player at the end of the table finally raises, they usually have it. At a beginners' table almost nobody is bluffing — people bet when they have something. Believe them.
Only the five shared cards are shown, which is all you need.