(i.e., constantly pecking kisses on each other, groping on a park bench, making out in the library, etc.)
I think some self-restraint should be exercised. I'm OK, with seeing someone give their SO a prompt kiss godd-bye, but when they begin sloshing tongues for 5 minutes, it gets irritating. Especially in the library. It's so quiet in there I can hear them breathing and sloshing saliva.