"Bob" writes

It's a PITA to have to scan through some times 2 or 3 or more
messages to get to a reply. Some of you think it's ridiculous to top
post, but that's your opinion, and I'm entitled to mine! As Bill
Murray would say, "that's the facts Jack"!

Most top posters tend to quote the entire posting.

First, we shouldn't quote the entire posting that we are responding
to because many people (especially outside the United States) have to
pay for their Internet access by the minute and/or by the amount of data
transferred.

Secondly, we shouldn't put our comments above the quoted material
because people who aren't directly involved in a discussion themselves
usually follow the logic more easily when they can read the material in
more-or-less chronological order.

And finally, it's completely unnecessary to quote people's "signatures" at
the ends of their postings since they just take up space.