I'm modeling a Master Ball from Pokemon that I'm going to 3D Print, but when I applied the subsurf modifier to the M it did something weird to a couple of the corners. I did some research, and I found nothing on how to fix it (Basically because I don't know what you would call whatever this kind of problem is). And I can't 3D print it with the model messed up like that. So if anyone could help with this, I would really appreciate it. Thank you.
I think if you rework it into all quads with the knife tool (pressing K) and then dissolve the unneeded edges it will work. Also: remove doubles. If it still doesn't look right: Sometimes you might think you hit the spot with the knife tool but you missed it. Zoom in to all the verts you connected and recheck. Make sure you cut all the way around to the back also.
Edit: Actually it is even easier. you only need to turn the top tris into a quad by dissolving its bottom edge and then add in two new edges with the knife tool.