Lying is one of those things that makes me lose respect.
Berating children in public is another thing.
Crap, I forgot....mistreatment of animal companions pisses me off and makes me lose respect.
I can't really answer the 1st question. Usually I like someone I respect. When my respect is lost, so is the like or love.
The difference is, friend and relationship:
If you have a friend you like, you automatically respect them and share common thoughts, when your in a relationship, the difference is, this person is bound to your heart, so to like them is one but respect is high.