Patric-san,
of course it's not a trouble at all!!
Good question! We actually distinguish sinks depending on the purpose of use.
流し is the kitchen sink where we 流す the water, washing up dishes
while 洗面台 is, as you see, the place we watch (= 洗) face (= 面).
We're not supposed to wash faces (and wash hands after using the loo...) or brush teeth in the kitchen.
My mother will be angry if I did
Natsuko (奈津子),
Team JapanesePod101.com