To some people the ego is evil. It gives you so much. It gives you everything you want. But it takes back too much in return. It gives you everything: money, riches, women, glamour, everything you want. But in return it takes back so much, and you're soulless. That's its goal. The ego's goal is to leave you soulless.
Thinking is compulsive: you can't stop, or so it seems. It is also addictive: you don't even want to stop, at least not until the suffering generated by the continuous mental noise becomes unbearable.