I think tipping is a very individual, very personal decision. When I went on my first cruise, I had no intention of tipping excursion guides. But the guides were so exceptional that I genuinely wanted to tip them as a way of thanking them. This really surprised me as I'm one who resents expected (and worse yet, automatic) tipping. But for me, "thank you" just wasn't enough. I actually enjoyed tipping the guides. But this was my personal choice. I tipped strictly because I wanted to, not because I felt pressured or obligated to do so.