Was reminded of this by reading something on another thread. Basically a friend had lost her mid 30s husband very suddenly in a horrific accident, leaving her with three young children. We were rallying around trying to help her and I went to her house to drop off some shopping and a non mutual friend (NMF) was there. I was asking her how she was coping and she commented that the loneliness was so hard, understandably. NMF said she could totally relate as her husband was a gamer and every night after dinner he would go upstairs to play, leaving her alone. She went on and on about how awful this was and got quite teary so that my friend was the one comforting her, telling her she understood etc. I sat in a state of utter disbelief, cringing for dear life at the utter lack of awareness and sensitivity of NMF. Any attempts by me to divert the attention back to my bereaved friend were in vain as NMF kept bringing it back to her situation. I eventually left but NMF couldn't "bear to leave as the house just felt so lonely" 
. I still feel embarrassed thinking about this years later.