The thing about the Mission is that there is no singular Mission to address. Maybe you're living above Mission Chinese with three of your closest friends, surrounded by rich hipsters, getting rabbled at by your elderly neighbor who has rent controlled his way through the changing demographic tides.
Maybe you co-created Burning Man and are living an upper-echelon hippie existence that no one really understands but goes to your parties nonetheless. Maybe you're a 24th St kid who's watched the street turn from pupusa windows to laptop cafes. You still skate to work and you go to trap night at Beauty Bar. But even Beauty Bar was once enemy No. 1 to the neighborhood.
SF is an amorphous thing that will never stop undergoing change. The best you can do in the face of turmoil is learn to love the quirks of your living space -- from the painted-over phone jacks and crown moulding with an agenda of its own, to the myriad noisy neighbors, insufferable landlords, and occasional houseguests. After all, it is your home sweet home.