Were Old Ceilings Ever Covered Up?For one thing, it should be noted that exposed beams in residential buildings were far less common than one might think. Wherever possible, and whenever money allowed, ceilings were closed up--even back in days of yore.
Closing up the ceiling serves several purposes. For one, this hides the unpainted, unfinished wood of the beams and of the floorboards supported by the beams. For another, it is much more efficient to heat a room when you have a lower and better-insulated ceiling.
Beams vs. JoistsBut the most important point is that joists are not beams. The post-and beam, or post-and-lintel, style of construction is one that does not apply to the majority of modern types of building. A joist is sized differently from a beam. You may find joists that are 2 x 10 inches or 2 x 12 inches, but not the square 4 x 4 or 6 x 6 dimensions that one might expect with the beam style.
Also, joists are spaced more frequently than beams. So if you open up the ceiling and look at it, the joists above might be spaced as frequently as 24 inches apart from each other. All of this means that you won't get anything close to the exposed beam style if you try to open up the ceiling and expose the joists.
Electrical, Acoustic ConsiderationsIf that isn't enough discouragement, you need to contend with the various wires that might be snaking through holes drilled through the joists. This means rerouting wires around the perimeter of the ceiling. Finally, you will need to accept the fact that sound will transmit more easily from floor to floor.
I know this from hard experience, having tried this once before in the callow youth of my remodeling experience. Nothing that I did seemed to help. I fixed the wires, reroute to them, plugged the holes, hit the joists and floorboards with white primer, repainted them--but it looked like exactly what it was, an open ceiling with a forest of joists.