These statements do seem fairly innocuous, and perhaps for most people they're just little stock phrases, little learned locutions we spit out in certain circumstances. I'm not concerned with this casual use, in the same way that I'm not trying to stop myself from saying "oh my god" or other things which are practically reflexes. I'm focusing here on people who actually believe in fate, or in some kind of force of karma, or that everything happens for a reason. These tend to be the same sorts of people who claim to be "spiritual, but not religious." This means that they like having ridiculous beliefs based on no evidence, but they also want to have the freedom to pick which ridiculous beliefs rather than conform to a preexisting dogma.
Here's the problem with beliefs of this sort: if you say (with complete intellectual honesty) that you believe that certain events are "fated" to happen (or not to happen), then the following things must be true, and by necessity:
- the universe, or someone/something within the universe, is consciously aware of the existence of every single person within it.
- the universe, or someone/something within the universe, cares about what happens to each individual and has planned out certain events (which are intertwined with the lives of other individuals).
- the universe, or someone/something within the universe, has some objective sense of morality (which coincidentally aligns with our own) and is concerned about keeping a balance.
- the universe, or someone/something within the universe, is sufficiently knowledgeable and capable of simultaneously taking care of every moment of every person's life in the world.
The most telling way to look at these beliefs is to ask why people hold them, and then it becomes clear why they exist. Ask someone who actually believes in fate or karma why he believes in it, and the answer will either be a blank stare (indicating that this person had never really bothered to think about that question before and has no real answer) or something along the lines of there just has to be something greater out there, something bigger than all of us, you know? Does there? Why? How can you possibly assert that that statement must be true? When you probe further, you will eventually get the person to admit that they believe it to be true simply because they desperately want it to be true, and so therefore it must be. Of course we would all choose to live in a universe that wants justice for everyone, but reality does not conform to our desires. The fact that you wouldn't want to live a life which is simply a string of random, meaningless events doesn't make it any less likely to be true.
Some people may also point to certain events in their lives which are seemingly so coincidental that there could be no possible explanation other than that the universe has guided everything to work out this one particular way. There are (at least) two problems with this line of "proof." First, coincidences are extremely common. Human beings live (on average) for nearly a century, and our lives are constantly intertwined with others' and full of all kinds of happenings and events every waking second of every day. This allows some extremely large number of opportunities for coincidences, and given such a large number of chances, the unexpected will inevitably happen, and happen a lot. We're much more likely to dwell on the one time something coincidental happens than we are the million times when it doesn't. To focus on the interesting to the exclusion of the mundane and assign meaning to the former rather than the latter is an arbitrary act inherent in human consciousness.
The second problem is closely related to the first: humans have an overactive tendency to pattern-match. That is, we see connections between unrelated events simply because they occurred at the same time, or sequentially. This predilection for explaining the world around us through cause-and-effect relationships gives an artificially-inflated sense of causality, which some people interpret as evidence for fate, karma, divine intervention, or whatever. We shouldn't feel bad though, as we're not the only species which is prone to superstition. Pigeons have been famously shown to behave this way as well.
If you actually believe that the universe or someone/something in it is sufficiently interested and capable of guiding events, you are obligated to explain why you believe this to be true. If you are unable to articulate the most basic information about this entity, such as where it is, what it's made of, how it works, where it came from, and why it's bothering to do all of these things, then how could anyone possibly believe you? How could you even believe it yourself?
There's nothing wrong with living in a universe that doesn't care about you. Really, it's ok. When something good happens, just be happy that something good happened. You don't need to thank anyone or call yourself blessed. Enjoy it and move on. When something bad happens, don't take it personally. Don't look up for help; do what you can to make it better.
Above all, as always, own your beliefs. Think about these things (I mean really think about them) and work it all out for yourself. Then stand up and be confident in what you've come up with, and be happy to talk about it with others. If you have questions you can't answer, go back and think again. Rinse and repeat.