odd flat tire issue
 

Yesterday morning I got off work and stopped at the supermarket. When walking out I noticed my back passenger tire was almost sitting on the rim. So I break out my cigarette lighter tire inflater and fill the tire from about 5 psi to 37 figuring ill be bleeding some pressure from what I assume is a slow leak, although I didn't hear air hissing or anything. I didn't notice if the tire was low leaving work or the night before since the driver side was facing me and I just hopped in the truck.

I get home, check tire pressure, still at 37 so I lowered to 33. I went out before work last night, still 33. Checked it this morning thinking maybe it had something to do with temperature drop overnight, still 33. So I think its safe to say I don't have a leak.

So aside from someone deflating one of my tires, why else would just one tire go flat only once?

I'm going with malicious activity.

Likely this. Speaking from my experience, when the temperature dropped rather suddenly on my old beater, I got a leak in one of the tires. Turned out the valve stem got a small crack in it due to the rapid temp change. If I kept it well inflated, the stem didn't leak much but once it dropped to a certain point, it leaked rather quickly.

Dry rotted tires do this too. If the tire is cracked and you park a certain way it will leak out quiet quickly.