Who the hell invented Polish?

My Polish lessons leave me with a mixture of elation (at having recognised words and managed to strings some of them together in sentences, even varying the tenses occasionally) and frustration (at being taught a whole new list of problems, er, I mean challenges, that are ahead of me). It all started when I learned 'to go' is iść. Then I learned that if you are in some form of transport it's jechać which I can deal with because I learned German. HOWEVER, it's not that simple, because if it is a frequent 'go' (in the sense 'every saturday I go shopping') it is chodzić and if it's a frequent 'go' using transport it is jeżdzić. This is just a minute sample of the intricacies of this language... we haven't even got to the fact that jechać is imperfect so if you want the perfect form you need to congugate pojechać. What a beautifully rich language... and what a bugger to learn.