You can get through life without quotations, but it's often more fun to use them. Actually, I'm not sure I've punctuated that last one correctly - I'll have to look it up.
Quotations can also frustrate.
You've heard it. Mathematically Speaking is a dictionary of quotations about mathematics, ably selected and arranged by C.C.Gaither and A.E. Cavazos-Gaither. As a bonus, it's got some nice cartoons in it as well. You can use it to look up a quotation on a particular subject, or you can browse and enjoy. It's even fun for non-mathematicians.