Plus sizes, dark circles and rudeness

I walked into the 'Health and glow' store, dreaming of a flirtation with the foreign brands, face creams and body washes. Unfortunately, the staff of the place had other plans.
"Excuse me ma'am, may I help you?"
"Just looking around," I used my customary reply which I had used so many times before in the hundreds of shopping malls.
"Madam, for you we have something here," the enthusiastic sales girl moved forward with officious zeal and steered me to a shelf. "Madam this is a new product in the market, it removes dark circles in just 2 weeks, they are claiming that otherwise they will give money back madam. And with this we have..."
I had to butt in to dampen her enthusiasm, and I did not mind doing so. Years of hearing such comments have now made me formulate a defensive-cum-offensive approach, to be customized according to the situation. "I am not looking for under-eye creams." My tone was firm and (I hope) polite.
Her smile vanished. "But madam, this will be good for you..." she persisted, albeit with one-fourth of her previous energy.
I instinctively looked at the large mirror on the wall in front of me. "I don't want an under-eye cream." My tone meant, 'Get lost'
"Ok madam, but this was good..."
It was time to get offensive. "Listen, in future, don't try this with anyone else. I am ok with my dark circles and I think they look great. I don't like it that you came to me and pointed them out, just because you need to sell your creams." It could have been more sophisticated, I know, but sometimes you need less tact and more force to get your point across.
There was the usual crowd of other salespeople coming forward to rescue the girl and I stepped out, hoping that they will not curse me too much to the girl and the girl will remember what I told her.

What gives someone, a perfect stranger, the right to point out your physical defficiencies? How would it feel, if someone pushes a fairnes cream towards a dark girl, or a weight reduction pill to a fat one? Though the offender will never understand it as anything else than 'being helpful', this simply makes me feel that the person is implying: 'you are an eyesore, so please improve your appearance so that my eyes can have something better to see.'

A week back, my colleague and friend was approached by our company's security manager at the gym. Hitherto, their interactions were limited to the gym, when she had asked his help to operate the treadmill, or to know if a machine which he had been using, was free for her to use. This day, however, he had a different agenda.
"How many working days does our company have in a week?"
My friend was taken aback. "Five," came her puzzled reply.
"And how many days do you come to the gym?"
My friend blushed. "Well, about three days a week."
Then followed some advice on how it was absolutely essentital to be regular, to attain your fitness objectives. Beats me, I always knew from the web and newspapers, that 3-4 days a week was enough to keep fit, except if you need to reduce weight and my friend was slightly on the heavy side.
I was pretty angry when she told me all this and added, "I am taking it positively."
Well, her approach was fine with me, his was not. In her place, I would have simply asked what prompted him to give me unwanted advice. Was it my size, and if not, then since when had his duties shifted from security to fitness?

How can people take liberties with someone else's dignity? What gives anyone a right to hurt a person's ego?

Last Friday, another friend of mine, who was again a regular patron of the Gia brand of plus size dresses at Westside, accompanied me to a supermarket. When I was weighing 3 dussheri mangoes, there was an old lady who was directly opposite to us, who smiled at her. She smiled back, obviously puzzled, and then I found her eyes fixed onto something, and her face registered disbelief. Moving behind her, I noticed the old lady waving a leaflet towards her with the following words on them:
'If I can lose weight, so can you.'

I suppose all those advice on being well-behaved with elders, drilled into her since her childhood, held my friend back. Or maybe, she was too shocked to speak.

I came away, very disgusted.
Well, these incidents are best forgotten as they will only tend to lower the self esteem. But who will tell a major part of Indian people that certain questions are rude, certain choices are personal and not everyone agrees with you about what is wrong with their nose?
Why don't people understand the difference between being helpful and being rude? Are we so de-sensitized to others?