I'm embarrassed to say that not once, but several times, I've collect loads of feeds and then rarely made good on reading them all.
The stuff I was interested in would change over time, so I was left with feeds I wasn't so interested in anymore. I tried different feedreaders. And I would always feel overwhelmed when I saw 4,283 unread messages.
So I'm back trying it again with a "must read" folder in Google Reader and only putting feeds in that I definitely want to read.
But when I do subscribe and am committed to reading, I try to make an effort to at least open every post and start reading it.