Why are humans so materialistic?

Two days ago I ve lost my husband's father. after a long period of suffering -a cancer.I had the right neither to ask for his pardon nor to attend his funeral.you're going to ask for the reason.No it isn't because am a horrible woman but in contrary because am not looking for the heritage..his wife and daughters are trying to push my husband and I far to get the heritage . Am not a materialistic woman because my second father loved me so much Alas..Agata cristy s' stories still exist.so I need your help Am so sad you know..