Why kissing or public display of affection is peculiar in some countries?

It' not a matter of morality, it's a matter of culture differences. People all over the world happen not to share the same culture. If it is the culture in your country that seeing lovers kissing passionately in public is okay, in most Asian countries that is unacceptable. Smacks and light kisses may be tolerated but anything beyond that shall make everyone's eyes go round in amazement. This is the reason why once we visit other countries, we shall always be reminded to observe and respect their beliefs and cultures. We may not necessarily observe them when we're back home again.

actually me as a filipina is quite conservative when it comes with that thing however, we have different beliefs, culture and traditions so we need to respect one another...though, public display of affection (PDA)is the only way for those partners where they can show their love with each other so with regards on that, we also need to accept the reality that we live in a modernized technology where some men and women follows on it :)

1. They are afraid the other half may be kissed by someone else. 2. They need public recognition 3. Open air is better than closed doors 4. Chances are, if other aspirtants who see this, never make another attempt;

I don't think it's morality but as I see here in Thailand, their culture does not approve of public display of emotion like kissing. Well, of course many foreigners do it and some Bangkokians are getting used to it. It's just a culturally influenced issue. But according to one song, If you're in Rome, be a Roman. It's always polite to observe the cultures and tradition of the country you're visiting.

But it somehow so over acting because you let people see everything that you do. And its bad.