PS?

PS? oohh!! PS stands for:

1. most obviously, Play Station! A dream I'm not all that interested in fulfilling...

But here in KMB, we have...
2. Photo System (group of pigments where chlorophyll is the reaction center, for photosynthesis. There is PSI and PSII in cyclic and non-cyclic light dependent reaction)
3. Personal Statement! (very important thing we need to write for our university interviews)

and others could mean:
4. Post Scriptum or PostScript as used in writing, P.s.
5. picosecond
6. Ps for Pastor
7. Power Steering
8. Plastic Surgery
and so on.

Hehhehehe