I think all examples aren't created equal. Their examples are complimenting a haircut you think is ugly and kissing someone when you're upset.
Complimenting a haircut you think is ugly can backfire. Instead of changing hairstyles, your partner might keep the one you said you liked, get made fun of, ask you about it and realise you actually didn't like it, and feel set up. This is an example where it doesn't affect just you.
Kissing someone when you're upset with them seems different to me, though. Now, I assume it doesn't mean "be upset but pretend you're not" because that much is bad. But with my boyfriend, even when we're really pissed at each other, we make it a point to still hug, kiss and say "I love you", to show each other that our love is bigger than the issue we're upset about, and that we'll make it though. I think that much is very healthy. Knowing the other person is upset yet still want to hold and kiss you is good for the relationship I believe.