do some players value bishops more than queen ?

I sometimes play with players which whatever happens they avoid trading their bishop, i felt that they would give up their queen but never trade the bishop, i have a cousin who have this thing in reverse he hates despises knights so much, he really did take my knight with his queen one day, with a victory smile, i just died laughing that day, is this common ?

I don't know if it is common chess behavior. Many experts regard the bishop as slightly better, on average, compared to the knight. On a complex and crowded board I prefer knights. With more open positions the bishop pair can be very powerful. A single bishop with a blocking pawn structure can be next to useless. A good workman will be able to use all his tools effectively and know their limitations and powers. Just blindly keeping the bishops irrespective of the position is foolish chess. Players who will trade their queen for two knights or two bishops arbitrarily are generally asking for a resounding defeat. There may be rare circumstances where sacrificing the queen for a smothered mate with a knight yields victory. Trading 2 rooks for a queen is entirely feasible and there are many examples of rooks against queen winning. Of course a strong player against a beginner could see all these chess principles thrown out the window. In the opening, I will often trade my knight for the opponent's bishop if that bishop looks dangerous. The value of pieces is often dynamic and a bishop blocked by it's own pawns can be next to worth less. A few moves later it may be worth 3 as it is unblocked. A bishop with unrestricted access to its diagonals can be worth much more than a rook stuck in a corner. A knight in closed position could be worth 4 points and on an open board less than 2 points. The value of pieces during the game is variable and during each game, decisions to exchange pieces should be made based on sound reasoning, strategic plans and tactical resources, not on some irrational favor of one piece over another.

@Moh001 #1
Most top GMs favor bishops over knights.

I believe GM Donner once wrote that the bishop pair has several advantages, one of them being that it is easy to choose when to trade pieces with them.
In endgames, especially in open positions the bishop pair can be very very strong.

There are exceptions however, GM Jobava seems to be a knight lover. Check his games and see how he often has a pair of knights, rather than the bishop pair.
And I read that GM Ulf Andersson prefers B+K in endgames rather than B+B.
Look at the games of GM Carlsen en GM Capablanca, and you will notice that they both do not mind giving up the bishop pair.
Look at the games of Bobby Fischer and you will see that he was a dedicated bishop lover.
There's a famous game Fischer-Petrosian, in which Fischer had a very strong knight on c5, and he traded it for a bad looking bishop on d7. The spectators, among others GM Najdorf, went beserk, and thought that Fischer lost his head when he gave up the strong knight, but Fischer continued to win the game in brilliant style.

I think the position matters. A strong knight in the centre can be better than a bishop. There is no general rule about strength that applies to all positions. It can be true that seen on the average a bishop is slightly better than a knight though.

K+B+B - K = won
K+N+N - K = draw

Extreme case.

@achja this made my day "There's a famous game Fischer-Petrosian, in which Fischer had a very strong knight on c5, and he traded it for a bad looking bishop on d7. The spectators, among others GM Najdorf, went beserk, and thought that Fischer lost his head when he gave up the strong knight, but Fischer continued to win the game in brilliant style."

In all honesty it depends on the position. If I was to start a game with ether knights or bishops I would pick the bishops just due to the long range ability. But if I could have a nicely placed knight or a blocked in bishop it would be the well placed knight. Same goes for me taking my opponents bishop it would really have to depend on the position if I wanted to give a knight for a bishop. Occasionally I have played the exchange Ruy mostly in blitz but I do not believe in it giving up a bishop rather uncontested.

@chessanalyst #6
I've just looked up the game :
en.lichess.org/aL7DR3w1#42
http://www.chessgames.com/perl/chessgame?gid=1044351

From the user comments (Jan-13-05 Hesam7) :
--- begin quote ---
Robert Byrne:
22.♘xd7+!?
<This brought the house down! GM Miguel Najdorf jumped up and started shouting, 'My God!! He's crazy!! Such a knight!! My God!! How can he give uo such a knight for such a terrrrrible bishop?' Of course no one else understood Bobby the way I did. You see I played a lot with Bobby and analysed with him at length. You see Bobby loved bishops. According to the way he played chess, Bobby was just driving the nails into the coffin. The bishop may look bad but it's not. The position is open. The c5-knight is great but it blocks the open c-file. Finally the d3-bishop is so much superior to a knight when there are pawns on both sides of the board. Bobby was just using his principles. As for the Soviets, GM Suetin smiled and showed a great sense of relief.>

31.♖ee7
<At this point I was so excited I could hardly glance up from my typewriter. I wanted it all be true Bobby was dismantling Petrosian and was on his way to meet Spassky. Of course thnervous as it involves some sacrifices iI hadn't worked out. I cast a glance at Soviet delegation and saw that GM Suetin 's mouth was wide open and he looked pale. A bit worried, I asked if he was alright? He turned, looked at me and murmured, 'My god, he plays so simply.' I turned back to my typewriter and laughed within myself so hard it hurt.>
--- end quote ---

I guess taking control of the c-file with his rook and the potential weakness of the a-pawn in abscense of the bishop are key points in Fischers plan.

Bishops are good for open positions because they can control more squares if played correctly. Knights are good blockaders if you have a grid lock type position to where the bishop can not pass the pawns. My advice is just play what you're most comfortable with. When I first learned that bishops are better it took me a while playing to realize it. If you're not comfortable playing with the bishop pair then see what your knights can do man! Confidence shows on the board.

Bishops are bloody fuckin amazing pieces! They're fast (getting across the board with few moves), they can control entire diagonals and they're just fuckin overall amazing.