How depressing. haha
To the OP: So if you know that it's probably not the wisest thing to get involved with whoever the person is that you're crushing on/in love with, then recognize and accept your feelings (btw, feelings shouldn't be the driving force in our decision making, but it's good to recognize them because they're often an indication of where our heart and mind are.) and carry on. Find other things that matter to you and are important to fill your thought life with so as not to obsess over the situation or that special person. Obsessing is never good or healthy.
Unless you're a professional stalker or something...
I have a tendency to think of all of the negative aspects of a possible relationship and then totally back off. Also not a good idea. It tends to make one a bit pessimistic and hopeless. Sad, but true.
Hopeful, excited and wise are good! Obsessive or pessimistic are both bad. lol