Or come across as creepy :). The article is well formed and I completely agree: a complement (generally) costs you nothing but can have outsized positive effect on a recipient.
And even _knowing_ this, I've generally not complemented the pretty dress that a lady is wearing on the train or at the store because, well, because imagined scenarios where I'm briskly turned away for the audacity to talk to such a person. To combat that and to not sound like I'm trying to strike up conversation, when I give compliments to strangers I do it casually and as I'm leaving their vicinity (for guys or girls). "That's a fantastic shirt," or "beautiful necklace" happens on my way out.
It also turns out I don't think I know how to take a complement. Like, I can say thank you, but feel pressure to give a complement and I prefer to give a genuine one but then worry it will come across as forced. This reciprocity is highlighted in the article. It is also a pattern used by folks preying on others. Overall, I feel I'm generally socially awkward and I've settled on the drive by complement with strangers. Folks I know, that's different.