These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complacent Gaming Syndrome: The Fire Flower/Super Leaf tandem. Unlike many Super Mario World hacks where the combo's required to pass (for example) the dreaded ice block-flip block patterns, in Mario Adventure it's just another one of the many power-up combinations that can see you safely through various stages.
Mostly bad from a player standpoint; later levels end with two Boom-Booms, but jumping on both at the same time results in Mario getting hit. Although this is clearly a glitch, it works out for the challenge of the game — otherwise, it'd be trivial to exploit them into staying together in a clump. Possibly a Throw It In.