I've only had 2 controllers say hello when boarding/disembarking and had a nice chat with them both... also had 2 on the jump seat (seperately I might add) which obviously gave a better chance for a chat. I'm more interested than some perhaps because my better half is about to start at NATS, but of all my colleagues I can't think of any would give the 'who cares' attitude you mention. I have to say though that you may have unintentionally caught the crew at a busy time (when pax boarding it can get a bit fraught with the odd problem rearing its head!) I'm not defending anyone who may have been rude though, there's no excuse for that! It is a shame you feel like that because none of us can do our job without each other and should maintain that 'family' feeling... I always find it good to see how each other feel about things, but thats why I try to visit the tower at any airport I'm based at and a couple of visits to Swanwick, not all of my colleagues do.
Hopefully you'll get a better response next time... if you're seated at the front, sometimes a quick word whilst the rest of the pax are getting off may be a little more relaxed, unless they're on a 15 min turnaround!
Cheers