As a dog lover and owner of a business it is very easy for me to see all the positives of allowing pets into our office. We do (have done for around a a year) and I strongly believe that they are an asset to a company's culture particularly around de-stressing, socialising and well-being with them needing a walk during the working day. 

There are potential problems that need to be considered though such as employees with pet allergies, noisy pets who could make for embarrassing phone calls, hyper pets who disturb employees and the likely inability for everyone to bring in their pet on the same day and risk creating a zoo for the day!

Overall though Pet Friendly offices are a great idea.