happy as a pig in muck
happy as a pig in muckBRITISH, INFORMAL
If you are happy as a pig in muck, you are very happy. From day one I adored it. I was as happy as a pig in muck. Note: This expression has several variations. For example, some people talk about being happy as a pig in shit. I'd much rather be as I am, I couldn't imagine being any different. Happy as a pig in shit. Frankly, I was like a pig in shit — oh, how I revelled in the opportunity of standing next to famous people!