Quick story from this week's game to illustrate my DMing style:
The PCs (2 clerics, a fighter/rogue, a fighter and a barbarian) are trying to escape a orc, ogre and giant infested fotress via a teleport circle they have to find. They have already been in a number of encounters and haven't had a chance to rest, so they are at like half strength. Last week's cliff hanger had them breaking through a door to see 6 ogres with Large Halberds waiting for them. When the session started, the party formed up and made the ogres come to them. these kinds of fights, I roll dice in front of the players. I also have the players roll dice for me on things that are arbitrary/random: in this case, how many rounds before reinforcements arrive (1d6, the player rolled a 6). So they are fighting smart and using tactics and when the rogue moves in for a sneak attack he gets critted. 30 points of damage (also rolled in front of the players). he doesn't go down. The ogres last for another round or two, so the Pcs have 2 rounds to get through the next door to find the portal. They do so, and slam and bar the door just as reinforcements, including an ogre with an enormous maul (warclub) to break down the door.
Now the PCs have to search out the teleport circle while the ogre tries to bash down the door to get to the PCs. I had another player roll for the ogre every round as the party searched.
That player -- rolling open on the table -- must have rolled more 4s, 7s and 8s than I have ever seen. The PCs were able to not only fidn the portal, but do some looting and battle prep.
Because my DMing style is what it is -- "let the dice fall where they may" is probably the best description -- we had an exciting, tense session. Had I fudged to soften the crit on the rogue, or just made up a number of rounds it took for reinforcements to arrive, or just decided the giant ogre with the huge club could make it through the door in two swings,things would have been very different, and, IMO, not nearly as fun.
Luckily, I have players that appreciate my style* now, rather than the ones that got mad when they lost, died or were simply in a tough sitaution.
*mostly. they still bug me about loot.