Some reasons you may try foiling and then stop or give up:
1. You get foil gear that makes learning really hard. Some guys can foil an anything, but regular guys really benefit from recent improvements.
2. You
hate crashing and learning new stuff.
3. You have severe balance problems (like inner ear issues).
4. You live somewhere where it is blowing like crazy every time you want to go windsurfing (if you do - where is that?).
I know real life examples of the first 2 issues, and know
of someone with issue #3. #4
might apply if you live in Brazil or Egyt

.
If none of the above applies, you'll probably love foiling. When you buy stuff, keep in mind that "mix & match" can create problems, since foils are often matched to boards from the same manufacturer.