People are in relationships with one another for all kinds of reasons. These include default (your family members, classmates); necessity (your professor or roommate); personal choice (friends, significant others); or happenstance (the loud guy in the seat adjacent yours in the stadium). While most times it's our closest relationships that cause us the most stress, even the most casual relationships with others can affect the way we feel about a situation, or ourselves. Additionally, learning to sustain healthy relationships and choosing to end (or not enter) unhealthy ones, are skills that can take a lifetime of practice.