I'm just curious. Because whenever someone tells me something about my blog (loading slow, comments being cut off) I look into it and fix it if necessary.
Whenever I run across a blog that is interesting to me, but I feel like there's an "issue" and I can offer a helpful suggestion, I leave them a comment or a message on Entrecard.
Some of these blogs have been on "Daily Visit" list for a long time, so when I tell them "Your sidebar is not showing up correctly", they take the time to reply and thank me for letting them know that their blog had an "issue".
Some of the blogs I see are ones I've never seen before, or on which I've never commented, so they may see my helpful suggestion as "Who the eff does this beeyatch think she is?"
I don't normally correct people's spelling or grammar. It's just something like "If you would change your template in this way, your sidebar would actually be a sidebar instead of a bunch of stuff that shows up after all of your posts." Only nicer, LOL.
It just irritates me that they have nothing to say.
Even when I think the person messaging me is full of doodoo (for some reason, Stewie from Family Guy comes to mind when I say that word & it cracks me up!), I thank them for letting me know! Common courtesy. I take the time to let you know something which may be an issue for ALL of your readers (not just me) and I think YOU should take the time to at least say "Thanks! I was not aware of that."