I hate you.
Don't we all. Benbot brings up a number of good points in his post, not least of which is that there are often no discernible visual cues that differentiate between terrain that can be traversed and terrain that can't, and the minimap often confuses this issue by making it appear as though you're right on top of a mission objective, when it's actually on the other side of hill that it's going to take 20 minutes to get around. Anybody whose ever been to Benefactor Valley in the The Divide will feel my pain. And unfortunately, it is something that's unlikely to be addressed with the current content, because of the work involved with going back to re-texture old terrain. That won't stop people from complaining about it though, or us from reporting on it!