Bit of a complex comparison. I will just point out a few:
Buck: At the time of ODST, he is the last of the original A-9 squad. He's working with people he does not really know well and having to operate in a new structure. He can be perceived as irritated, but he's simply under a lot of strain. Maybe his way of dealing with the problem is pushing ahead regardless of the obstacles or people's feelings. i.e. Romeo's commenting
Romeo: I can relate to Romeo's need to fill the air with comments. Obviously, Buck found this annoying and told him to zip it.
Chief (343's): He's entering a new world that has moved passed him. In Halo 4, he has been gone for many years. He is no longer special in the aspects of being a Spartan. People are becoming newer, faster, and stronger. He needs to adapt to a new world or risk becoming obsolete.