I've never had someone in front ask me before reclining and I don't mind as that is part of the design. I do be careful around mealtimes though or if there's anything that can be knocked over.
On the flip side, I don't ask if I'd like to recline, though I do it carefully and not at mealtimes.
I don't see why people complain about people reclining. Shouldn't it be expected if that's what the design allows? They should really be complaining about the plane design instead.
I'd get a bit annoyed if there was a child reclining like crazy in front, but I don't think I'd do much other than huff a bit...