This tutorial explains how to prevent Google Hangouts from displaying animated emojis in your conversations. Hangouts automatically converts text/word like "happy birthday", "woot" or "yay" into animated emojis and some users might find this feature annoying.
Open your web browser, connect to your Google+ account and click on Hangouts icon displayed at the top right corner of your screen:
Scroll to Chat Options and clear the Convert text to emoji checkbox:
This new setting automatically applies to all your Hangouts conversations.