Was at some "food trucks and beer" in the park thing near my friend's place and they had some of those hot girls in skimpy outfits who hand out like shots of energy drinks or tequila or whatever to promote the brand. Explorative I know, but also free tequila.
Anyway, one was like "holy shit you have the hugest calf muscles" (I work on my feet and do a lot of hiking), and like kept going on about it. "Damn do you run or something? It looks like you have bowling balls strapped to your legs."
And I was a bit like 
I got a mild ego boost from that.
Same! I've been trying to reframe it for myself lately, since I think it's genuinely a good thing to do.
If I complement a stranger and they don't like it, it's because of things that other folks have done where compliments were used as a foot in the door.
I am not doing that. If they knew my true intentions (hyping them up with no strings attached), they would not react that way.
I can not control their reaction, but I will try to demonstrate my intentions by giving them the compliment and then disengaging.
If they think I'm a creep or hitting on them after that, it is not a reflection of me personally, but a reflection of how they have been treated by society. And honestly, I'm kinda sad for them. They live in a world where compliments are often given with impure intentions.
Even for that person, paying a well-intentioned compliment is helpful. If they started getting a ton of compliments from people who genuinely just wanted to make them happy, then their attitude would start to shift.
I want to embody the society that I want to live in, because society shifts only when enough people do that. I want my behavior to stand out from the crowd, because that means people will think about whether what I'm doing is right. My hope is that they decide that they should also behave like I do. Propaganda of the deed of being a good human.
I'm willing to accept some social consequences in service of that (e.g. some people thinking I'm a creep). I will be open to changing my mind, of course, but social consequences are expected when you're trying to change social norms.