By and large in most sane operations the ex service stuff is just a bit of banter for crewroom use only.
You do get the odd one (odd in more than one sense of the word) who still thinks he's in uniform. Most are more than happy to move on.
I only came across one operation where there was genuine nasty side to the ex service relationship.
I happened to walk into the the office behind the chief engineer and his deputy both ex crabs and was quite horrified to hear what was going on.
They were sorting out c.v's for a vacancy and the conversation went
ex army no, ex navy no e.t.c.
There was genuine animosity towards ex navy/army, which extended to training not being provided and a very nasty atmosphere.
You weren't in their little clique and they let you know it.
Thankfully a one off for me.
I find the ex service mix is all part of fun with each group including the civvies bringing their own expertise and quirky humour to the job.