These are perfect situations to see how your GF act's.
Taking ownership of your lack of percieved qualities when a girl is flirting with a guy say's more about the type of guy you are than the type of girl your with.
The only right thing you did here was going out with your friends after the meal.
Ideally what you want to attract is a girl who doesn't feel the need to flirt with every guy, be it a waiter or a guy in a bar.
Yes you can adopt a certain frame and techniques to peek her interest but when all is said and done, if your girl is flirting with a waiter in your face, you can class it has a sure sign that, that girl is most probably for sport fcuking only.
How would I act?
I'd act like I always do, watch how she preforms with the onslaught of another coc* in the vincinity and judge her actions accordingly, what I wouldn't do is preform like some monkey swinging my dic* to see who has the biggest. At the end of the day i'm not that competetive when it comes to puss*, what I mean is - if I am out on a date the last thing on my mind is having to worry about other men around, that shi* is the first sign of insecurity, mind games and head fuc*.
I remember a time when I was dating this solid 9.5, we was in a bar, this good looking guy, well built came over to me and my girl, he had a bag with him, he reaches his bag out, hands it to the girl I was with and asks her to save it for him whilst he goes to the toilet. He comes back sits on the other side of the girl, she moved closer to me - good sign - so he gets up and starts talking to some other girls - I forget about him, do my thing, get up and go to the loo - low and behold I come back and he is sat in my seat, talking to the girl - I simply walked over to him and said "thats my seat" -
Then i forgot about him, yeh the girl i was with peaked at the guy being Alpha, did she respond, did she open him, did she encourage him? No! That is the point, if she would have done, i'd have probably left her hanging and let her get on with it, then waited for the inevitable phone call 20minutes later asking where I was, or simply spent the rest of the evening with her and then put her in a cab and never called her again.
I definatly wouldn't be the guy sitting awkward whilst my date and another guy fluffed, with me hugging my pint or thinking of some clever shi* to say to try to out-alpha the guy - fuc* that cra*.
Some peoples adivce for such things are more or less "chat to some other girls in the bar, to make her jealous" I call BS on that one too, if your out on a date, you've got ready, you've invested your time in going out with this chick, for her to drift towards the flirting of an other guy, no man on the planet is going to be in the comfortable enough zone to go and chat another chick up - if anything he is going to be a little pee-d off - also to go and chat other girls up shows your trying to out Alpha the guy - whats the point in that cra*, unless the girl is for sport fuc*ing, what about the times your not there to show her how alpha you are when another jock comes on the scene.
I've just read all responses, seems like this was a free meal ticket, hence the lack of respect on her part in flirting - taking girls to dinner or drinks aside, Robert you did the right thing by going out with your friends afterwards and i'll give you props for not getting invested and developing AFC tendencies to a girl because she went on a date with you - Very DJ handling of the situation, you saw the damage and acted accordingly, but next time, skip the dinner date cra* - and when a jock comes over to your girl, watch her actions - but stand your ground and only act if the situation needs you too, i.e the fcuker doesn't pis* off when your girl tells him to.