For me, I really enjoy doing Mentor roulette because you don't know where is it going to throw you this time. And it feels good to help new players.

You don't really have to give advice all the time or tell the party what to do. Some groups can handle themselves just fine. It is when you notice something that is considered wrong (Example: tank wearing DEX gear instead of VIT) or about to start a boss fight that can cause a wipe if not done right.

Mentors with bad reputations are mostly those who are farming the mentor titles or the mount. They speed run through everything and any party mistakes or wipes cause them to lose their temper.

If you really want to be a mentor, go for it