Weird Shading, Please help!!!

Hi everyone. I would really aprecciate your help in telling me how to turn off this weird shading that appears in my viewport in Blender. It only shows up in Blender 2.7, and it’s been driving me crazy since I first downloaded it. It has obviously something to do with the normals, since it’s only noticeable on one side of the object, and everytime i flip them, it changes its side. It does not affect my work at all, but it is just really annoying when working in the viewport.
Sorry for my bad inglish, if so, and thanks a lot.

Im new as well, but i have noticed if i close and re-open blender, or i re-do the step i want, it then behaves.

Doubled sided normals looks to be what you want.
Properties Window > Object Data > Normals: Double Sided

On complex scenes or when sculpting high detail meshes, it may slow down your computer.

Thank you so much. I knew for sure that was it, i just didn’t know where to go. For the record, I’m not new at all; this was just one of the basic things I should 've known and i didn’t. Thanks so much!

Double sided checkbox will not fix the basic problem that your normals are pointing in the wrong direction - IMO it only serves to mask the problem that some verts on an unclosed mesh are facing in the opposite direction from the others. While it looks ok in the viewport, incorrect normals will cause you huge problems in normal maps, UV unwrapping and a whole lot of other operations that consider normal direction.

Not to take away from the other advice or to suggest that you aren’t aware of this, just a heads up.

I’m not sure if I’m following you. As far as I know, my normals are just fine; the part of the object that is seen in the image right above is the inside part of my mesh, not the outside, therefore, normals are suposed to be facing the other way. My only problem was that i didn’t like that kind of shading for the opposite normal-facing direction, which i had never seen before and, as long as it may be useful to recognise which direction the normals are facing, i find it unnecesary. If I missfollowed your point, please let me know so I can know what you are talking about.