I think this impression comes from two things:
1) A lot people thing long combats are boring - and I think it is b/c they do some variation of the old "You miss", "it hits", "you hit", "it misses" etc. . . kind of combat
2) the DM/Players is/are not taking advantage of the environment and the inherent drama of the situation to make it more fun and more strategic of a fight.
Environment is super important to all the great fight scenes in nearly every movie or book we have come to love and are trying to emulate.
Standing there and getting full attacks on each other is only always the best option when there is a level playing. . . uh,
fighting field - but if your enemy can get cover or concealment, or get above you, or threaten innocents, or has some piece of information needed by the PCs and can't be killed but fights and moves in a reckless almost suicidal manner (so you have to try to defeat and save him at the same time), and a ton more examples I can give (hmmm, maybe I should write a PDF product

) the fights are going to be more involved, a lot longer and a lot more fun.
Sure sometimes, some fights are gonna be a straight up exchange of blows, it can't be avoided - but that certainly should not be usual case.
If you check out my story hour (see sig) you will see the following kinds of fights:
- a battle in a sewage drainage chamber beneath the complex of a huge tribe of orcs, with unseen pitfalls and explosive gas and vicious orc toddlers.
- a running battle to escape a collapsing subterranean necropolis
- a hit and run/hide fight against a psionic manticore amid the ruins of an old mansion on a hill.
- a four way battle between the above manticore, a powerful evil sorcerer, a wizard of unclear allegiances, and some town guards who were escorting the majority of the party weapon and armorless, chained to the back of a wagon to seek the king's justice
I think you get the point