go and (do something)
To be so foolish, negligent, unfortunate, or thoughtless as to do something. "Go and" in this sense is used as a modifier to express or intensify a negative sentiment regarding the action. You can have a few cookies as a snack, but don't go and spoil your appetite for dinner! I had the money in my pocket to cover rent for this month, but I went and spent it all at the bar.
This phrase is an intensifier, that is, it heightens the action indicated by the verb that follows it. For example, Don't go and eat all the leftover chicken is stronger than "Don't eat all the leftover chicken." Similarly, Thomas Gray put it in a letter (1760): "But now she has gone ... and married that Monsieur de Wolmar." Sometimes the and is omitted, as in Go tell Dad dinner is ready, or Go fly a kite, colloquial imperatives telling someone to do something. [c. 1300]