I often feel the same way.
On the other hand, I've been on the receiving end of someone who sends emails just to tell me, in a not very nice way, that I've been a lousy friend because I never respond to her emails. Not nice at all. I've told her over and over that if the email attacks me, I don't respond. This friend is what I call high maintenance and she's probably the only person I really hesitate to respond to. If it's to let me know in an appropriate way that I've hurt her feelings, I'll respond fairly quickly. Sometimes I need a day to think it over. The key is it needs to be non-combative.