I don't know this who this guy is or how he played, but establishing a pattern for your opponents bets (and getting your opponents to respect your bets based on previous hands) is a massive part of the game.
Once patterns are established the good player will mess with them in order to induce a call or fold as appropriate (your guy may have been skillful enough to only show the hands where he had strength and may have been betting lesser hands in a similar fashion in order to induce folds when required).
The main thing is that although varying bets is a good thing, there are certain sizes of bet for certain hands that pay off the most in the long run.
Limping AA is occassionally the right thing to do and may land a big pot, but it's real value is when raised between x and y times the big blind.
Similarly there are occassions when it is worth raising low pocket pairs and Axs, but generally seeing a cheap flop and hoping to hit is the way to make them pay.
If you know what the optimum way to play each hand is from each position and can peg how your opponent plays, you can reduce their possible holdings to a few options in most cases.
(that got long quick and may or may not be coherant

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