The exposures, hands, and outcomes here are illustrative. They use only general, public-domain reading principles (exposed sets reveal what a player is collecting; already-discarded tiles are safe) and are not drawn from any year's official card.
Your ledger
A good reader is right about the table more often than not. The result line is allowed to disagree.
Play a few rounds and the pattern will show itself.
Four reads this drill is built on
Defense is not fear. It is arithmetic you do before you discard.
Read the exposure before you feed it
An opponent's exposed pungs and kongs are the only reliable tell you get. American mahjong has no chow \u2014 every exposure is a group of identical tiles \u2014 so anything you see face up is a tile they were collecting, and feeding it is feeding that group directly. Two exposed sets means a player is a tile or two from a hand. The mistake nearly every improving player makes is pushing into that board because their own hand "felt close." It wasn't close enough.
Already-discarded tiles are free discards
A tile no one can possibly use against you (it is already in someone's discard pile, or in a suit nobody is collecting) cannot deal you a losing hand. A safe fold is never a mistake, even when the table turned out quiet. You could not have known it was quiet, so discarding safely was still the right arithmetic.
Pushing into exposure that missed is the dangerous one
When you feed an obvious board and it happens not to connect, your brain files the push as a success. That is how the worst habit gets trained: luck paid you for a poor read, and the next time you push into exposure you will remember the lucky miss, not the rule.
Count the right reads, not the wins
The win is decided by whose hand lands first and what they drew, none of which you controlled. The read is the part you control: did you fold a hot board, and push a cold one? Over a season the reads compound; the single-round result is just weather.