I would say do whatever you feel comfortable doing, but for me an 1/8 did nothing, the walls were breathing and I felt happy but it wasn't until I did a 1/4 that I really felt anything, and it was amazing!!! I think what helped for me was that I didn't think you could have a bad trip of shrooms, I thought that was reserved only for acid and so it never even crossed my mind. I have never had a bad trip of shrooms. I would also say if you have done acid b4 just go ahead and take a 1/4, does not even compare.
^^^The last time I tripped I took a 1/4 (mostly fat caps) and tripped for 22 hours!!!! After 19 or 20 hrs I was running through my neighborhood screaming and yelling at the top of my lungs for it to just stop, I thought God was just fucking with mind..... So I mean you can take a 1/4 but I wouldnt recommend it. But dude telling this person that it can only do good is bullshit... That was the ONLY bad trip I ever had but it was F***ing HORRIBLE!!!!!!!!!!