To get away from work/writing (including Hub-writing) for (usually) little bits of time at a time. In other words, to break up my work time on a site where I already write Hubs and earn money (and therefore, may as well spend "break time" too).
I do "day-job work" on the computer. Then I do writing for myself (away from the Internet, or sometimes not, but on the computer.) Then I do my more casual, free-time, writing as a way of earning a little extra money beyond the more "serious" efforts. I don't do any online socializing anywhere but here, because I'm not inclined and don't have the time to "get all into" socializing sites.
So, since I already know this site and already come to it to do things like look for any comments or check for things like broken links, it's just easy to use this site as the site where I look to get away from writing/work and just look for something else. Also, I often get ideas for writing (on here or elsewhere) from discussions in the forums (or from "Answers", of course).
My "breaks" can come in the form of several one- or three- minute quick visits here, or I may spend an hour in the morning (while I'm having coffee) just seeing what's on here (and not "straining my brain" too early :) ). OR, I may have only a couple of five-minute visits in one day, but then on a day when I don't have much work I may just decide to relax and waste time on here (but not writing Hubs because I want to relax) for a couple/few hours. I just think of my HP time (Hub-writing or other stuff) as "instead of watching television" or "instead of spending the same total amount of time that others spend on things like Facebook, or "whatever". Since I learn about what's happening on/with the site, know (sort of) a lot of the community members, or else get some ideas for future writing, it just kind of all fits together and makes sense. Then, too, sometimes I just need a little useless-waste-of-time kind of activity. :) If I can answer someone's question about HubPages while I'm on here anyway, it's easy enough to add that to the mix. I don't really care what I do when I take my little breaks. I mostly just like to scan for anything new that has showed up and might be interesting for a minute or two. If I think something like a forum discussion may take me longer than a couple of minutes I'll come back when I have more time and am in the mood.