Remembering PIN number so annoying ! Is there any solution ?

It's so annoying when you cannot remember your pin , when there is a long que behind you . So many things to remember you password for Facebook , Twitter , Blog , Mail and so many things . On the other hand if you got like 4  or 5 credit or debit cards , it's so easy to mix it up. I mean come on its human mind not some kind of machine you know. When I receive payment from customer , I get that a lot people trying to remember pin or looking to his/ her mobile or there is small note in his/her wallet/ purse just to put the pin. Once I was paying my tuition fees , I used like 2 or 3 cards & mixed up like several times to put the pin in , the admin gave me an attitude the I am irresponsible . I mean I don't want that kind of attitude or to think him that I am stupid or fool. Don't you think there should be like , you don't actually have to remember or use pin & also it should be secure. What about your finger print ? Why any industry invent something like biometric , just use your finger print & job done & also it would be secure. I mean no one actuall can borrow your finger to use your money & only way to do is actually cut your finger & use it. You don't have to carry all the cards with you as well. For online it can work as well , because remember on I- phone before you  get started you have to use your finger print , They take it from you to keep the record. Has anyone ever thought that & you don't have to actually fill all the details from your card as well . How much time could  have been saved & all the hassle could have been removed. One of the industries should think about this.