Now, after thinking a little bit about it I figured that yes, we weren't really in the mood. But then I wondered, why weren't we in the mood? The answer I found is: because we have didn't any specific goal to attain. If we knew why we were infiltrating then, maybe, we would have been interested in what we were doing and who we were talking to. As it was, our only goal was to "make friends", which isn't a very compelling goal in a rpg... And anyway, it didn't take any real concentration to figure out how to make friends (just say "your right!" a couple of time and here it goes ;), so we didn't have to be in the mood to achieve our goal. Another thing that might have caught our attention is if our live was threatened, which wasn't the case. In that situation we could have been playing better, I admit it, but we had no real incentive to do so.
To get back to Shadowrun, this might happen too in this wonderful game we all learned to love. When the gm doesn't give any precise goal the players tend to be out-of-game a good part of the time. How to remedy to this? Give an objective, but not the way to get to it, so you won't be railroading the players. The objective might change mid-game, of course, but there should always be a precise goal. If the players search what to do next and wander aimlessly, have some npc give them something to do that might get them back on track.
Another thing, always have some reason regarding why what the runners are doing is important to their goal, even if it's false. Players don't usually care for a situation that they regard as non-important, even if, in reality, it is. You must keep their interest, so putting irrevelent stuff will just bore them to death. Would you like a movie where half an hour is spent doing irrevelent stuff, for which you don't care? Of course not, and it's the same thing in a Shadowrun game. A good way to make a situation (which shouldn't always be used) is to put the runners life at sake. If the players care for their characters, they will listen. If they don't, then kill them, they don't like their character anyway!
So, overall, to have players who are concentrated on the game and care for what happens you must keep them interested. To do so you must give the players a goal that is clear and atteinable (so you don't have them discouraged) and for which they can find ways to get to it (having to wait for the gm to give you the information you need because you can't find it by yourself is just plain boring). To keep the players interested you must always give them a good reason regarding why what they are doing is important to their (or one of their) goal. If you can't find any reason then that part doesn't have any use and must be skipped (remember though that a scene that is not useful might be revelent. The encounter with a contact who actually don't know anything shouldn't be skipped because there is a reason to encounter it.).