It is selfish to take your roommates parking spot.
Jim lives with his roomate Tom, and feels a little lonely when Tom is at work.
Jim wants to invite some company over.
Jim goes to pick up his friend and drives him back to his place to watch movies.
Jim invites his friend over to watch movies and tells him to park in Tom's spot.
Jim is able to have company over and Tom has an easy time parking his car when he gets home from work.
Tom comes home to find his parking spot taken and circles the parking lot for hours before finding somewhere to park.