I've bought two of these mugs. They both leaked coffee all over my shirt and the mug. I've tried tightening it judiciously and firm, both ways they leaked. The lid doesn't seat evenly on the mug, so of course it's going to leak. It's cockeyed, which only leads me to believe it's a manufacturing error. Unfortunately for me I'm the recipient of two leaky mugs. OF COURSE I bought these for coffee...If I want to carry hot soup I'll buy a thermos. It's unacceptable for a mug of this price and supposed quality to ever leak.