Just to highlight what Olivier said in a comment, make sure you keep your version of angular and angular-animate in sync.
From bower.json
Good
"dependencies": {
"angular": "~1.4.6",
"angular-animate": "~1.4.6",
Bad – out of sync
"dependencies": {
"angular": "~1.4.0",
"angular-animate": "~1.4.6",