Just say no!  

Once you start mining you can't stop.  

You keep telling yourself ROI is right around the corner, then difficulty goes up, and you invest in another miner.  You finally get some regular BTC coming in, then it slows down again in a couple weeks.  NEED MORE HASHPOWER!

It's a disease.  If you're just in it to hobby and speculate, go ahead (that's what I told myself too).

But be very careful...once you see that Bitcoin Core wallet popup saying you have an incoming payment, it's over...