Girls are not complicated it's only that they have different moods and wants which shift with time. It is probably due to hormones which makes them hard to understand. The best advice is stop trying to understand them but just love them deeply.
God grant me the strength to change the things I can change, the serenity to accept the things I can not change. And the wisdom to know the difference. Serenity I think must be the answer to things we cant change. Nearly everyone is complicated in some ways. Figure out which complications are acceptable ones for you, and which ones arent. Then you will have an idea of what you want as a person. Try not to settle for anyless than what you can deal with. goodluck.
Ah, one of Life's great mysteries! Men think women are complicated because women are emotional and men are rational. We think things through, they talk about their feelings. But God made us different for a reason. If puzzle pieces were the same, they wouldn't fit together.