I still feel I missed a great oppurtunity of working for(with) you.

以下是引用quaint在2004-5-27 0:29:01的发言：
I have always regretted not having worked for/with you.

regret is used in two ways

1: To miss someone or to mourn the loss of death of someone.

2: To be very sorry for something.

The second is the one we often use, so if you say you regret something,
that is more like you feel sorry for something. Such as we regret we ran over
your daughter with our SUV.