I'm a beginner, I started learning blender a week ago, I followed a lot of tutorials on youtube on how to fix and prevent some common beginner problems, but I really don't know what's is going on on my mesh.
Since it is hard to explain I made a little video showing the problem on my mesh: http://sendvid.com/flt8t55s
I already checked for doubles, already recalculated normals.
If I apply a Subdivide Surface modifier all those strange shadows disappear and everything appear smooth, but from what I've learned so far, it is a bad thing to use Modifiers to fix some of the problem that shouldn't be there.
So I want to know what's could be the problem.