In Yoreh Deah, there is a rule: "Eidi detarach lemiphlat lo bala - When meat discharges fluid, it cannot absorb," for the direction of movement is contrary to absorption. The same holds true in the reverse. If absorption is occurring, discharging cannot simultaneously occur.
This notion applies to all of nature, including human nature. If one is exclusively predisposed to absorbing, to receiving, to acquiring, he will have a most difficult time giving, helping and perceiving the needs of others.
(Rabbi Shmuel Yaakov Klein)