The way to fix this sort of problem is to redefine the relevant list environment. The enumitem package is my favourite way to do this sort of thing; it has many options and parameters that can be varied, either for all lists or for each list individually.
Here’s how to do (something like) what it is I think you want:
\usepackage{enumitem}
\setlist{nolistsep}
or
\usepackage{enumitem}
\setlist{nosep}