Adding a small “loader gif” is a nice feature to add to your site if you know that the page takes a second or two to load additional content, especially if its via ajax. But the key to that last sentence is “a second or two”… If your site takes longer than that to load additional ajax content, then you need to revisit your code and make it faster, and probably remove some unnecessary loops and / or bugs.  I was on a site recently which started off by showing my a simple loading message:

Then after about 10 – 15 seconds of showing me that message, it changed to this one:

Then after another 15 seconds or so, it switched to this one:

Please never do this on your website… If you ever find yourself creating error messages like that, fix the problem at hand, don’t mask it with a witty message like “Taking a while! Bear with us…”. No one wants to bear with you, they only want to leave your site.