Which Azure service do you find yourself using the most, and why?

I’d probably say Azure Monitor, honestly. It’s one of those services you don’t always think about first, but once you’re supporting real systems, it becomes something you rely on all the time.
It helps me see what’s going on across apps, servers, databases, and other resources without having to guess. If someone says an app is slow or something failed overnight, Azure Monitor usually gives me the first clues.
The biggest lesson I’ve learned is to set it up early and keep alerts simple. Too many alerts just become noise. Good monitoring should help you spot problems quickly, not create more work.