Tech Support “Secrets”

Looking for anonymous help from the experts for a story:

For folks in tech support:

What are top 5 problems you’re called for?
What are stupidest things system users do without knowing it?
What don’t they “get about what your job entails?
If you could give them two or three “all purpose” hardware/software tricks to remember, what would they be?
How secure is their data, really?

Thanks!