The greatest gift a parent can give a child is unconditional love. As a child wanders and strays, finding his bearings, he needs a sense of absolute love from a parent. There's nothing wrong with tough love, as long as the love is unconditional.
The law demands good works and uses its terror--rejection, shame, fear of punishment, unanswered prayer, personal tragedy, etc.--as motivation. Here performance is a necessity to secure the blessings and avoid the curses. Grace, on the other hand, allows us to serve on a different basis--not from fear but on the basis of love and gratitude, from appreciation and gladness for blessings freely given and freely received.