The grumpy variety normally originates from the officer hating WO and is determined not to let his new status get in the way of his dislike of "blue bloods". He is determined to spend as much time as possible in the Sgts Mess generally doing as much damage to Sgts / Offrs mess relations as humanly possible. Disliked but feared by both, everyone will be very happy when he finally buggers off to command a training area somewhere.
TA officers' messes can be heavily infested by these types.
More interesting is the chilled out variety. He has seen it all and is now quietly amused by it. Other than the NAAFI manageress, he is the most informed member of the Bn. Everybody trusts him, and he sits back and watches the Majors climb over each other in the back-stabbing career race, the subbies being clueless and the Captains whinge and meanwhile receives 'how it really is' from the Sgts Mess, to which he is nothing short of a god.
That's it really. Oh, and I started this as a warning - never trust the fuckers with the Torygraph crossword.
There is a third variety of LE officer: the Careerist. The obvious characteristic of the careerist is that, as soon as he's persuaded his fatt-ish, jolly-ish wife to unpick the WO1's badge from his service dress, he trades her in for a more 'upscale' officer-issue version. She will be horsey, own a labrador and speak 'proper'; she will almost certainly be divorced from a Major in the RLC and have a couple of teenaged children in tow. He is fit, keen and desperately trying to look younger than he is. Mr Careerist knows all the angles: he knows exactly which job he needs to get posted to in order to get rapid promotion and maximise his pension, and he's on first name terms with everyone in his MCM branch. It all goes horribly wrong when he's found getting a blow-job from the assistant adjutant in the TV room after a Regimental Dinner.