I'm on a 4 dev team (one of many). 3 of us commit to only do what we are pretty sure we can do. One of our team commits to way more than they should. Guess w

I'm on a 4 dev team (one of many). 3 of us commit to only do what we are pretty sure we can do. One of our team commits to way more than they should. Guess which of us is always carrying over stories and whose new functionality creates new bugs ever sprint? They never can wrap stuff up completely, they are like a tar ball of chaos. Unfortunately they are supposed to be our tech lead so all we can do is shake our head and watch.