I like random encounters.
They’re the most fun when it’s a surprise, not just for the players but also for the DM. Is it going to be a combat encounter or a role-playing encounter? Will the party fight or parley? Will the party attack openly or try to sneak past? Will it be hard or a cakewalk?
You just don’t know because it’s random.
This can be problematic if they’re a clear combat encounter and the monster requires some heavy management. 4th Edition was particularly ill suited for random encounters as it meant 2-5 monsters the DM had to read the unique powers of on the fly. And because encounters were long set-piece affairs it meant having an encounter for what amounts to thematic reasons (emphasising it is not safe and monsters are everywhere) was not always the best idea. Not that 3e/Pathfinder are much better, with their laundry list of feats and options that might need to be looked up before running a beast.
But in many ways, that’s a plus. If the DM doesn’t want a fight then they’re not going to push for a fight. It makes you think in different ways and improvise instead of just going with the default action of hitting party members until they stop moving. Suddenly the orc warband might be friendly or already injured and returning from a failed raid. And that’s where the game becomes interesting…