Yeah i think it is a part of the game. To be an unpredictable player is a key@ cash tables and also in tournaments.
Shells said:
Poker isn’t just a game of math—it’s a game of behaviour and actions...Am I right?!
Yes you are right. the game has his own dynamic way, can change the style in minutes so it is on you how you react and act from this.
In my mind an unpredictable player is somebody who plays a wide range, my advice is that you try to beat him with solid hands and play it a bit slower and passive. I wouldnt check-raise such a player if you dont have a monster because you get committed fast in such pots with that style of player, so i would prefer a check call situation if it cheap to see flop/ turn.
Try to figure out with which hole cards the unpredictable player goes in to showdowns and the actions step by step before, it is necessary to analyse such a player if he is a "good" regular player which tries to bluff at good spots or an unpredictable "maniac".