Of the six "types" of engineering nothing is broader then mechanical. Mix and match almost every type of physics, then place it in R&D, Manufacturing, Maintenance, Quality, Safety, and a bunch of other areas of practice and you end up with hundreds of answers.
For the most part , I was in film production, special effects, or game technology. I love a good story well told. SO thats my thing. Every assignment was unique... I even set up a "doggy cam" . Yup its what you think...
Keep asking that question ... to a lot of people... The HVAC engineer stuck in your vent will probably have a completely different answer than the dude dodging the helicopter rotors, even though both involve moving air around.
Do a shadow day at a facility or place that interests you. The more answers you get , the more you see your future in one of the answers.
Probably not mine.
Rich "Houston, we solved a problem" Wolf