Bars

I went tot he bar last night with a couple of girl friends and basically dropped 50 bucks. Im not complaining because i wasnt the only guy buying drinks all night, but the girls walked away, maybe dropping $10, and never offering to even buy rounds once. Now, i know its the guys responsiblity to pay for most of the drinks throughout the night, but shouldnt the girls at least offer, espeically when you consider them friends?

Also, should a girl at least speak to you after you buy them a round? (im not saying this is the case for me, but my friend last night bought a round for a girl and she didnt even say thank you)