The first facility I bought rained INSIDE the building;) I didn't know that a non climate controlled facility should still have insulation to prevent condensation. I live in NY and we had a 70 degree sunny day in January...so the hot roof caused the cold air inside the building to condensate in big ways! Had to pull up 10K square foot of roof, insulate and re-install the roof. Also dealt with the annoyances of glitchy gates before I resolved that issue and have had a few break-ins at various properties but we've always caught the bad guys in the end. And even with all that stuff, I can safely say Storage is my favorite asset class on the planet. Even after factoring in those "horror stories" they pale in comparison to the ones from my landlording days!
I also just spent $81K to replace a roof on a 45K square foot conversion project (after spending $15K to TRY but fail to fix it;)..... And that was after spending $40K to replace a wall. Both were surprises. Fortunately we bought the property for $3.65 per square foot so the money was there to fix it right!
Rereading this post makes me feel like I don't do anything but screw up;)....I'll resist the urge to counter the above with all the things that have gone well for us in this industry;)!