I made a bunch of businesses cards, but I am afraid I may have messed up the grammar... I have been reading now about commas, and it is possible that the ones before "but" should not be there. I believe they are "unnecessary", since the two parts of the sentences present separate actions, but in the second parts the nouns are missing. Also, not sure about the commas at the end of each line and the capital letters after them. Can anybody tell me if there are any mistakes? Thanks!
The commas are fine because if you were speaking those words you would pause at just those points, and you can mark a pause in speaking with a comma if you want to.
If you were really being picky then you would not begin successive clauses of the same sentence with a capital letter. But I doubt whether being picky is the right attitude to approach a humorous business card. In my opinion the text looks better with capital letters there than without.
And, what is more, it is conventional to begin successive lines of poetry with a capital letter whether or not they are at the beginning of a new sentence. It is certainly arguable that what you have on the card is humorous verse rather than prose.