What Men Shouldn't Criticize With Women

Some work friends and I were recently discussing things that men can not criticize their girlfriends about. It was astounding how incorrect us guys were when trying to lay out our "rights" in terms of constructive criticism. The women in the office were appalled at what we thought we were allowed to talk about. If I could figure out what I am allowed to criticize and what I should stay away from, I'd avoid arguments and do a better job of hitting on girls.
I'm guilty of saying things to women that only their best girlfriends, gay male friends, and moms/sisters are allowed to say. I put together a list below:
Weight
There is no friendly way for a guy to tell a girl that she's put on weight. Even if there was a friendly way, most of the women I've talked to about it said they would not want to hear it from a guy. It seems obvious, but not all guys know this. We polled some of the guys in our office, and the prevailing male opinion was as long as she's your girlfriend, or you've known each other for a while, then you can make weight loss suggestions. I think the best policy is silence. If I"m desperate to make a suggestion, maybe I tell one of her girlfriends to do it on my behalf.
Outfit
I think I'm only allowed to say someone generally looks nice, or I like her shirt or whatever. Getting too detailed or negative gets me in trouble. In fact, I attempted to "add on" to a compliment I gave a girl once. I told her she looked great, because she had a new outfit on. Now, remembering those times I saw my sisters or friends bark back "thanks, and just $30 from Target," I tried to double up on my compliment: "and it looks like you didn't pay much money either." She ended up crying. I've been told by women that they dress more to impress other women anyway, and not guys. Basically, I need to stick to "you look great" and leave it there. And I should probably avoid saying I don't like something a girl is wearing. That can only lead to no good.
Friends/Family
We've all dated people with annoying friends. But, people consider their friends as extensions of themselves so if you criticize friends, you're criticizing your significant other indirectly. My older sister has a good system of putting the word "that" in front of any of her husband's friends that annoy her. "Oh you're going with that Mike to the concert?" It's not an aggressive attack, just a little poke. Family is the same rule, but you probably get in even more trouble if you criticize the family of a significant other.
Driving
Every guy thinks he's a better driver than his girlfriend. I can learn a lot from my little sister's boyfriend. One day, my sister was driving the two of us to Baltimore for a weekend. My sister is a really bad driver. She doesn't brake when she sees brake lights ahead until she absolutely has to. This leads to passenger whiplash and nausea. During this trip I said: "you know, you can brake earlier- that way you're not slamming on the brakes at the last minute and making us all sick." She said: "do I do that?" I turned around to her boyfriend for confirmation and he simply said: "no comment". My sister's boyfriend loves me because I am allowed to verbalize all the criticisms that he's thinking.
I like the "no comment" policy. But I can't stand not to give my opinion to women, even when it's bad. I want to learn the things I should hold off from criticizing about women. Do you agree with the items above? What do you hate being criticized about by guys?
Follow me on Twitter: twitter.com/richravensPosted by Rich