I know what you mean, spotting queens used to seen as some sort of rite of passage and I was never quite sure why.
Most of the time you really don't need to see her. If you open up, the workers are relatively calm and stay on the combs and you can see eggs, then its a pretty good basis for assuming she is present and correct at least within the last three days. Just go about your business as to why you were inspecting them. You will probably spot her anyway.
I do make a habit of spotting the queen being the objective of the first inspection of the year when the colony is still small and then marking her with a dot of paint on the thorax. This makes picking her out the rest of the year a bit easier. I also wing clip my queens then or on the next inspection. Its optional of course and some don't wish to (which is fine). By making more of the abdomen visible it actually accentuates it and makes the queen even more obvious. Maybe we should start another thread on clipping, it always surprises me how nervous folk are to consider it.
If you open up an otherwise docile colony and they immediately "lift" off en masse and are quite aggressive, after making space by removing the outer frame or dummy, I would immediately go to a middle of the box frame and shake off all the bees back into the hive and check in good light for eggs. If there were no eggs to be seen and plenty of empty polished cells, I would be thinking queenless and only then make a methodical search for her and to discover what is occurring.
The another time it could be important is when you think they have swarmed and are looking to split. The books usually suggest they will have swarmed once the first queen cell is capped however if you have a clipped queen it often is not the case and she will still be there - as will all the workers you might otherwise have lost in the swarm.
Most of the rest of the time its fun to spot her but not essential, unless you can think of other occasions you might need to?