My HONEST opinion? Well....not always.

If you are doing improv, there is a very good chance that you are connected with almost everyone in the local improv community where you live. I am always asked my opinion from performers who are just starting out in improv. they will invite me to a show, and then ask for my honest opinion. Sorry to tell you-in most instances, what I am giving you is not going to be my honest opinion. I beleive in encouraging junior talent instead of squashing it. If you are really that bad, I know you will eventually get that feedback from someone else, so it doesnt have to be me. I am more interested in you as a person. If you are a nice person and a bad improviser, I will be nurturing and complimentary to you. If however, in the rare instance that you are a bad person and a bad improviser, I will set you straight on both accounts. ONLY if you ask me.
Otherwise I beleive in keeping my mouth shut and moving on.

Now having said that...I will also state, if our relationship is professional, like you are taking a class from me, and I am your improv instructor...I will be honest. I will be encouraging, and positive, but honest. Instead of saying "you suck." I will tell you that it is premature for you to be onstage in front of a paying audience, and to continue working on your skills. I will identify the skills you need to work on, and help you monitor and track your progress. I will show you other people who are doing it correctly, and expose you to excercises that will help you.

Worse come to worse...in the no win scenario, I would encourage someone to invest in conventional acting instead of improvisational acting.