Geez, I feel like pulling out the Vizzini speach regarding what some of you consider railroading.
I once played with a GM who was nothing but railroad.
We had a special boat that could go 60mph. But he would "intercept" us with normal galleys. I tried to explain the physics of that one, how we could avoid any normal boat if we chose to, but he insisted that we had to have these encounters. Got nothing special out of them, so we were never sure why we HAD to have those encounters.
We got sick of his railroading us into a plot we had no interest in, so we decided to leave the town, which was a port on the edge of a desert. We try to hire a ship. No one will take us. We offer many times the going rate. No takers. We try to buy a ship, even for much more than it is worth. No takers. We try to gear up to cross the desert, but are warned off doing that.
So we resolve to steal a ship. We attack at night with a really good plan. Every last crew member on the ship is on the deck, fully armed, on round 2. Longboats full of town guards are crossing the harbor and boarding the ship in a single round.
Ah, but we soon discover that he will NOT kill us! We're all at low single-digit hitpoints and suddenly no one can hit us.
Then the ship somehow catches fire. Over about 5-6 rounds, it burns to the waterline, mysteriously doing so without injury to any of us or the people we're fighting.
"The ship is going to sink. What do you do?"
"WE DROWN!!!" (wads of character sheets rain down on GM)
This same guy once argued with a player during a combat, insisting that the player's dwarf "must" (somehow) be up on a ledge that he couldn't have climbed, fighting the wizard there. They were screaming at each other, moving the character's mini back and forth between where the GM wanted him to be, and where the character walked into the cavern and attacked the closest enemies.
You just ain't never been railroaded until your GM insists that your character is doing something that neither you nor your character would ever even remotely consider doing. Or refuses to allow you to do the simplest of tasks because they would interfere with the story he has created.