Pawn grabbing is a bad habit.
Whenever there is a tendency to grab pawns in your chess game think again. And here is the reason as to why.
At its heart, chess is a logical game: if your opponent repeatedly violates opening or middle-game principles (usually to attain a small material plus is not a good reason), he or she will have to face the repercussions in due course.
Usually, a player will neglect his development in favor of material gain like a pawn capture, because he sees no immediate tactical refutation. This stems from the fact that he assumes he will find a way to neutralize his opponent’s development initiative in due course.
Carlsen seems to prefer always taking a pawn, as long as there is no obvious loss – but he is not a normal player like us guys in the fishpond!. He even did it in game 5 vs Anand in November 2014.
Have a look below.
This position arose after some moves in the Sicilian Rossolimo Variation. Black just grabbed a pawn at h4.
In closing remember that modern chess is not dogmatic; the rules are not written in stone. There are genuine cases when pawn grabbing is tactically justified (the Poisoned Pawn Variation of the Najdorf Defense comes to my mind).