Noun
Debbie Downer (plural Debbie Downers)
(informal, derogatory) A naysayer; one whose negative remarks depress or dissuade others.
I don't want to be a Debbie Downer, but…
Booth regulations can be a Debbie Downer but can also be a great creative challenge – how will you conceptualize and build out the space within the booth constraints?” Source: Internet
Isolation and limited support – this negative outlook can often times push people away (aka Debbie Downer). Source: Internet