How is Derry's and Mr. Lamb's behaviour and attitude different towards people because of their physical impairment ?

mr. lamb had a positive approach towards life. he was optimistic enough and satisfied with what he had. he respected and appreciated every aspect of nature. he took everything in a positive note, for instance, the kids called him 'lamey-lamb, which never deterred his attitude towards ppl, whom he refer to as his friends.
on the other hand, derry's mind was filled with hopelessness and despondency. he hated to face ppl or even talk to them. he enjoyed desolation. for him ppl were just mere ppl, who viewed him as a disgrace. he thought ppl had a negative approach towards him and so his mother. seeing this, mr. lamb tries to sow a seed of hope and positivity in derry's heart.