I've got a special ringtone for both my T and my parents (different tones, of course). It's interesting...as soon as I hear T's ringtone, depending on my mood, I either feel a deep sense of relief or I start to panic. As soon as I hear my parents ringtone, I usually think 'seriously, you're calling again. I don't want to talk to you right now!' and then have to decide whether or not to answer...I don't always do so.