I dont like to invade privacy so when Im in someones home I try to gather as much detail as I can without actually touching anything, so no opening drawers that arent already open or closely examining objects that isnt out in the open. It requires a little more thought but you can gather a lot of info on someone by just observing.

As for eavesdropping unless im trespassing on someones private property i wont actively try to avoid hearing someones conversation unless it particularly disgusts/disintrests me.

I also do a lot of facebook stalking