Howcome girls show no love?

Like i dnt get it!! my girlfriend and i been dating for awhile and when we txt she shows no love to me like i do to her for example, wut im talking about. Ill say something sweet like, i havnt seen her in like a week and i said, "Im soo excited to see you tonight, I will kisss you and wont stop! =) mwah" and she replys back "lol" im like wtf?!! and out of the blue sometimes cuz im at work or something ill txt her mwah mwah mwah and i jus get a smile face or lol and its like i get no kisses back? ...... i kno that she loves me and she knows that i love her, it just feels like im showing her all my love for her and she doesnt show me love. i would love for to jus come out of the blue and say, "your such a wonderful boyfriend i love you with all my heart" or " im the luckiest girl in this world to be with a guy like you" u kno like i come out of the blue and say **** to her like that but i dnt from her..... i tlk to ppl about it at work and they say its like that with most girls they dont show love and im like why?? sooo if anyone as any opioins pleasse help me i would apprecite it =)