My friend and I are traipsing through the Temple of Elemental Evil. We've had about 10 4-hour sessions so far, and we're still on the first dungeon level (not the upstairs temple with the funky pattern, but the one below it). Our DM is getting frustrated.

We want to be thorough. We think this is a great dungeon and we want to see every room of it. The DM, on the other hand, wants us to get on with it already. He constantly makes snide remarks about how long we're taking, and even sent in two characters from the "government" (a knight and a wizard) to "ensure that the party is taking care of the problem". He thought it would push us to go faster, but no. We now simply have more support for our encounters, and we continue to steadfastly explore every nook and cranny.

He gave us a map of the floor we're on, which I'm allowed to mark on. I've shaded in the areas that we've been to, and there's honestly not much left. I thought we were making great progress, and we're getting a ton of EXP to boot. Our characters even have a reason for taking their time -- neither of them really have "save the world" on their agenda, they were just lured in by the promise of power and riches. Yeah, we're going to do the whole hero bit, but we want to get our treasure and EXP first.

It's coming to a point where we're starting to take our time out of spite rather than out of a desire to explore. He's just constantly on our backs and it's starting to ruin the fun of the adventure. Either way, he did a bit of a poor job making the actual point of the quest very clear -- the only thing I really know or remember from the minor encounters and plot expositions is that
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we have a couple of daggers and they're really nasty, and there's probably some encounters within the Temple that will have to do with saving the world. And something about a cult. Which is somehow tied to the daggers. Oh, there were letters. And I think the moathouse was somehow important.
For me, anyway, I'm more inclined to take my time and explore if I don't feel a pressing need to do anything plot-important -- and there really doesn't seem to be a pressing need to do anything plot-important in our sessions.

What's wrong with wanting to explore a really awesome dungeon? (And get lots of EXP before you go on to the more deadlier levels?) How would you handle it? And do you prefer to burn through dungeons or see every inch of them?