This is a little embarrassing, but...
The other day I got a flat on my ride in to work. I replaced the tube that night and pumped it up to ~120psi (road bike, btw). The next morning it was completely flat with what looked like a small tear in it.
I replaced this tube with another and only pumped it to ~100psi. Then the morning after, it too was completely flat, with a similar tear!
I've never had problems with changing a flat before, but I'm trying to understand this. It's my first time changing flats on a road bike but I didn't think that would make too much difference.
Any ideas? I'm still shocked by the whole thing; changing a flat shouldn't be this difficult.