First, screen shots are essential for understanding this. Embed them in a post using the camera icon on the web page, like this:
Second, you are almost certainly looking at the ffi ligature or you've turned ligatures off and you have collisions (that's why we need screen shots). Most people would say the ligatures are preferable to three independent glyphs, a la Word.
Third, for well made fonts the only time you should use Optical kerning is when mixing glyphs from different fonts or font styles, as in putting a script, italic or bold glyph next to a roman character in the same word. Even for badly made fonts you probably only need to change a few kerning pairs, which can be handled by a GREP style that applies a charater style to adjust the tracking on that pair.
The top view is a ligature, the bottom is the separated glyphs. Ligatures are very tradtional typesetting, a mark of a well-made font, and are enabled by default in ID, one of the many features most pros appreciate.
If you don't want to use them you should clear the Ligatures check box in the Basic Character Formats section of your paragraph style definitions. You'll also find a listing for them in the flyout menu on the Control Panel.