I've been diagnosed SPD in 2005, with dysthymia. I've come to realize that I have learned to be "content" with unhappiness, as a state of "normal." This probably also contributes to why my work history is a series of jobs that never last beyond two years. Poor social relations to supervisors/managers and coworkers.
If you are with someone with SPD, the best thing is to try to understand their quirks/behaviors and not try to "fix" them. Telling them how they are socially stunted dummies doesn't help. Sarcasm can be confusing, sometimes not recognized or understood.