1. Support - Having a bf/gf is gd for moral support esp if u have problems at home is gd BUT if he/she encourage u 2 go against ur family then..it will be bad.
2. Tutor - Having some1 to help u in ur studies will definitely helps. Its like having a free tuition. BUT if ur taught bad stuff like smoking, indulging in sexual activities..then it becomes bad.
3. Companion - It can be lonely at times esp if u have working parents. Thus having a bf/gf helps to ease the loneliness BUT if you use the opportunity to bring him/her home to the empty house, then it becomes another story. U get wat i mean...bad company...bad very bad..

I guess these are basically the reasons..it has its 2 sides. Semuanya ada yg baik dan yg buruk.. pucuk pangkal hati masing2. Tapi zaman remaja darah muda.. mudah terpengaruh dan mudah goyah. Senang cakap.. mudah terjerumus dengan perkara2 yang tidak sihat kalau iman tidak kuat. Hey.. we are only human right but do u have discipline and strength..well..u ask yourself. Tepuk dada tanya selera.