There is one thing I really like about testing (shortly neglecting all the myriads of other things I really like about testing): When you're testing you are using your brain in ways you wouldn't normally use. Let me elaborate.
As a Tester, I'm part of a team. The team wants to deliver a product and the people I work with have designed and built the product. People I care about have put a lot of effort in making this work - and now they hand it to me for testing. And there, first challenge: go against your instincts. Yes, I want this to work, badly - my team built this! So I start testing and it looks good, and than you get that quietly nagging feeling in your stomach, that if you'd click this button twice, and than turn over there, it's quite likely to break. And you really don't want to leave the good path you've been on so far, but that's exactly what you'll need to do here. Listen to the gut feelings, be aware of your instincts, and be prepared to go against them if the job at hand needs you to do so. (Ha. Another beauty of my job: Apply judgement when testing, there is always a context - when testing for usability for example, you actually need to go with your instincts. Love it).
When you're testing you need to go to where the pain is. You don't want to go there, your instincts will yell at you not to go there. But you need to challenge yourself to still do it, and you will also need to challenge your team to go there. You will have to bring up all the painful subjects, put salt into the wound and than twist the knife some more - but it's your job to do so. Be decent about it and your team will appreciate your efforts.
It encourages you to be more aware. It forces you to not be lazy in your head. You're brain will want you to be lazy - it wouldn't have to do so much, it wouldn't need that many ressources, it could relax, leading you only on the pathes that you've used so often, you don't need to think about it twice. People you work with, the developers of your software are often very similar to yourself, you might be sharing some background. They will think along similar lines, they will walk along the same pathes. These pathes will be well lit, they will be paved, straight, they will work. You need to walk on these pathes. But you will also need to walk everywhere else. And sometimes you might need to fly.
It's not about a list to be checked off (You need to do this, too, but don't stop there). Testing is a lot about creativity. Thinking outside of the box. Exploring the unknown. It's about to boldly go where no one has gone before. Being a Tester can be hard, and I think it's difficult, but I always found it worth it. It's constant learning. It let's you grow. It might even make you a better person altogether. And it will always make me smile.
