Why is Trump so unpopular in Russia?
Because he didn't improve bilateral relations. Also state-owned MSM still don't criticize him personally.
http://www.gallup-international.com/wp-content/uploads/2017/12/2017_Global-Leaders.pdf
There are actually countries where Trump is popular ...
Results for Austria (... where Trump actually isn't the worst rated leader):
Pope Francis: 70-16 (+54)
Macron: 55-27 (+28)
Merkel: 47-45 (+2)
Modi: 16-24 (-8)
Xi: 25-40 (-15)
Rouhani: 17-39 (-22)
May: 27-52 (-25)
Netanyahu: 15-46 (-31)
Putin: 29-60 (-31)
King Salman: 11-50 (-39)
Trump: 12-80 (-68)
Erdogan: 3-88 (-85)
By country:
Why is Trump so popular in Vietnam and Albania? These two are a bit puzzling to me.
Vietnam likes everyone
Nigeria and Ghana are also equally puzzling.