Granted I am still pre op, but I have lost almost 40 pounds and I am down from a 24 pant to an 18 and almost everytime I see someone that I have not seen since the weight loss is...
"Did you dye your hair or something?" LOL It's not super noticable, but they notice "something".

When I went back to work after surgery, for weeks, it was about my hair. Yes, I had gotten a new haircut, but there were several who would just rave about my haircut. Ask for my stylists name, because they could believe what a great cut it was for my face.

It actually tickled me quite a bit.

Sometimes it might be that they actually do notice but are afraid of being impolite so they don't ask if you've lost weight.  But they hope you'll tell them about it if they ask about your appearance in some way.

 I rarely ever ask/talk about weight with women unless we are really close.  I never ask if women are pregnant either.  It could be that they are waiting for you to say something about the weight loss.

My neighbor asked me about weight loss the other day (I lost about 50lbs since we moved in) and mostly she was asking so that I would comment on her weight loss.  I'm fine with that.  People can be so funny.

 some people just don't really pay attention either.  I found it funny that i saw a friend of my daughters mom at teachers conferences..now i am not out a lot and i don't have a lot of friends but i noticed she has lost a lot of weight so i mentioned it and she just gleamed she was so proud of her 70 lb loss..which is awesome but never ever even noticed my almost 60 lb. loss.  I didn't expect her too but it was funny thinking about it and how unaware she is that i lost all that weight too.  
One day at a school concert of my daughters another friend of mine came up to me and was all raving about how lucky i was..i thought it was about my weight loss but nope it was about my new job.  lol  but people look at me differently and i think they know something is up but don't know what.  And one of my FB friends congratulated me last night on my weight loss but she sees some random posts on FB i am sure.  lol  She was the first to notice though in almost 3 months.  ha!!

My husband and I used to laugh because I was constantly getting asked if I did something different with my hair..or people would say they didn't recognize me at first because "my hair must be different or something".  It was really funny.  It made me laugh. 

 I recently had a customer compliment me and he carefully asked if I had been loosing weight...then he apologized for the question because it's something he doesn't do...like asking a woman how old she is.

 The girl I work with says" your face looks smaller but I can't tell u r losing" I have lost 30 pounds so many people have said they can tell my best friend said girl I work w is jelous! But it is hurtful but I guess that is just her...people r so rude!