That might sound like a silly question, but...
Over time, and some good internet connections, I've built up a share ratio of 6.6 on this site (much larger on some other sites), with a download buffer of 35 TB. I'm not likely to go to ratio jail any time in the next hundred years. (I'm not bragging about size. Mousing around the "active users" list on the home page shows members with ratios in the twenties.)
By definition, having a good ratio is a good thing. But I remember my early days on this site, trying hard to get my statistics above water, and now it occurs to me that every GB I upload is a GB that someone else isn't uploading--and maybe that someone else needs more upload opportunity to stay afloat. Members with struggling ratios might have a better chance if I throttled my upload a bit.
I'm curious about other members' views on this topic. There isn't a specific "right answer" here, which is perhaps what makes this interesting.