I've always taken an approach of "always be respectful to everyone" - not just to be a kind person, but also because you never know when someone may reciprocate

I've always taken an approach of "always be respectful to everyone" - not just to be a kind person, but also because you never know when someone may reciprocate that kindness. In some cases, mere acquaintances have turned around to introduce me to job candidates, customers, business partners, etc. This approach works in the social world too, in terms of dating ;-)