How to get weird angles out of my Mesh

Hello,

So I was doing some character moedling and as I keep adjusting my mesh with a subsurf modifier some very annoying angles appear from time to time which i cannot straighten out (see pics). Sometimes the collapse-command does help but on the other side, I would prefer to just straighten out these Lines. How can I do this safely?




Go and actually look at your mesh without the subsurf enabled so you can easily identify your poor modelling

General guidelines:
Remove duplicate vertices
Remove internal faces
Remove floating edges
Use quad faces unless they are on planar surfaces