It's had a long history of annoying design decisions and increasing bloat. You can't edit payroll rates manually so you have to subscribe to their rate download service. It's chock full of offers and reminders for this or that service or paper supplies. It (as of ver 2011) installs 2 or 3 services that always run, one even if you aren't using the subscription service it is related to. It preloads itself on boot so it will start fast later (it is not a fast loader by any means). And they rewrote the report selection module in WPF, AFAICT soley to provide a useless Cover Flow ripoff view of the available reports (and they aren't even thumbnails of actual data or anything).
2) Whatever the Time Machine wannabee real-time backup software that comes with Western Digital My Book USB drives is called. Another WPF disaster (frankly utility type programs are not a good fit for such a heavy framework), that I shouldn't have been suprised wouldn't run well on our crappy old machines, but damn I was shocked what a bloated pig it was. Not the kind of thing you want to leave running all the time.
3) And for another bloated AV program to throw on the fire, Trend Micro. Their old OfficeScan used to be quite svelte. Whatever they call their latest monstrosity (it goes by several names) sucks up an appropriately monsterous amount of RAM and likely needs a couple of cores to itself to run efficiently.