Which british act was most offensive

There isn't one that was the MOST offensive. This question is truly your opinion, and if it was given as an assignment, you probably just have to prove your answer. This would be my response: 
The Quartering Acts were the most offensive for various reasons. First of all, unlike the Stamp and Townshend Acts, the Quartering Acts invaded the colonists' privacy, not their money/financial problems. The colonists' privacy is far more important than money, which is why the Quartering Acts would be the most offensive British Act placed on the colonists. 

I'm pretty sure that's called a volcano