In bash, what are potential negative consequences of pausing a process with control-z?

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http://unix.stackexchange.com – Using bash, one can pause a process with control-z. However, are there any general circumstances or guidelines to beware of where a process would not behave well with being paused? My specific scenario was in creating a tar file that was taking longer than expected. I wanted to pause it to put it in the background, but decided not to. My question isn't, of course, specific to tar. Rather, I'm hoping to understand the pausing feature in bash a bit better as well as what would make a process react poorly to being paused. (HowTos)