I would say my biggest insecurity is not getting (enough) useful straightforward feedback from my boss about how I work.
I have a tendency to take a bit longer than others, but deliver code that rarely has to be fixed.
Some of it may appear overengineered but it really isn't... I just like it clean and not hacky.
There are times my boss seems like telling me subconciously that I take too long for my stuff, but then again, he is really happy when we deliver a big thing to a customer and it just works, without any bugs or negative feedback.
It sometimes drives me nuts. 😅