They couldn't get the paperwork right. From the first time I signed up and was issued a box, the paperwork was screwed up in some royal fashion, I would thoroughly read it and point out that they messed it up (always unfavorable to me) and they'd fix it up apologetically. This is a bank. Bankers do paperwork for a living and their livelihood depends on dotting "i"s and crossing "t"s, so to speak!
The worst experience was the second visit when I discovered that my keys no longer worked. Well, I'd brought only one key of course, and when we discovered that it had stopped working, they demanded for me to go back and bring in the twin key to test that one too. Of course it was jammed. I was absolutely appalled. The "senior relationship manager" said the boxes are old and tend to seize up like that. I demanded a letter in writing with their proposal to drill the lock and rekey it, for free, under my supervision.
So I came in on the Drill Day and, you know how they have that little private Viewing Room where you put the box, open it, and inspect its contents? Well, the drilling contractor had put all his tools and toolbox inside that room, so it was full of valuable property already. I was sort of flabbergasted at the clear security breaches they were committing, constantly. This is a bank!!!
So eventually I caught wind that safe deposit boxes are completely deprecated. The last straw is when I asked the banker what would happen in a power outage - could I retrieve my belongings? He said nah, the last power outage they had, the cameras stopped working so they closed and wouldn't allow any customers in. Well, shit, one purpose of having offsite storage was to stash some cash and emergency supplies in case the shit hits the fan, and they're telling me it'll be off-limits in case of the slightest outage or civil unrest.
So I decided that an SDB is useless for my (or anyone's) purposes and I closed it out and said bye-bye. They never screw up the paperwork on my checking or savings accounts.