The truth is, though of course your very existence justifies your existence – but the following is a very good insight shared by my grandfather from the Rebbe – a parent loves all his children equally – though one may God-forbid be mentally challenged, as it is your child, your love is unconditional – however, the child the parent will receive pride from, is the successful child – so though you need not justify your existence, for the fact, you exist, is God’s act of love – nonetheless, to make both God and perhaps equally as important yourself proud of you, you must do something meaningful