Whatever you talk about will affect you also. If you talk about happiness and blessings, you will feel happiness around you. But if you talk about sadness and grief, then it will also have an effect. It is not wrong to talk about losses or grief when discussing anything in constructive manner, however we should avoid SAD POETRY because it serves no purpose and only increases our sadness. Islam also prohibits such poetry and poetry with constructive messages like that by Allama Iqbal instead is more valued by Islamic standards.