It's always said that a lot of success and opportunities are attributed to being in the right place at the right time (aka "luck"), but in a lot of cases, those folks had the tenacity to be in the right place ALL the time; when opportunities arise, they typically go to whoever's present and available.

Chatting with professors after class or attending office hours might be a grift, but it's not necessarily unfair. Specific circumstances aside, anybody can do it to get some leverage.