I've decided to start punching them in the face and saying "it was meant to be."

When people ask me if I believe in God, my answer is which god are you referring> They always come back and say there is only one god so I reply praise Allah and then I am told he is not the real god.
So what the hell are they asking except do I believe in their god, not my definition.
No more of this pompous shit, NO more. Define your god before getting an answer.

Horseshit! That is what I really do say. Most don't agree or like it, but it is my right to voice my opinion.

Take responsibility for you own damn life.

Ask them "How do you know?"

Most replies to that question are simply amusing by the measure of their ignorance...

My retort usually something like this.
Cancer.
Because it was meant to be, and gods will.
He is after all, a loving god.

If everything is God's will, he must be one cruel sadistic bastard.

'God's will' and 'Thank God' are two that annoy me. Depending on the situation, my usual comment is "god had nothing to do with it".

I ask "Then why did you bother to pray if it was predetermined?".

"Good, no one can blame me."
"I knew there had to be a reason."
"I knew it wasn't my fault."
"I know I didn't do it."

Sometimes I will correct them and say it was Zeus or Apollo's way just to prove how absurd it sounds when they invoke God's will.

Usually an eye roll and a heavy sigh.

Reply is really? what a nasty god.

It's an easy statement to make when it's not your nut sack infested with cancer.

So that means children with terminal conditions was meant to be? Having to watch your child die was meant to be? Children missing limbs or having hideous disfigurements was meant to be?

I don’t say anything, I just nod, & may say unhuh. That’s not the time to discuss the meaning of life

Shit happens!

It all depends on the situation. I don't tend to take anything like that personally. I sneeze, someone says "bless you" and I reply with a thank you. They sneeze, I say "gezundheit", and they reply with a thank you. Most interactions are just that, in passing and fundamentally meaningless except for the shared positivity.
If someone is talking about their life and replies "well it was meant to be" I am not going to be confrontational about it. It's none of my business, really, I'm there to empathize. Now, if they ask me a direct question, well then I'm going to answer honestly while still being empathetic.
Case in point, my brother is a Church of Christ minister. Yeah, he's way high on some primo Jesus, and that's what makes him happy. I'm not here to take that away from him. The vast majority of our relationship is completely non-religious in any way. How're my nieces doing, the wife, the dog, etc. Is your work at the Church going well. Yep, I'll ask him about that. It's his job, and he's my brother, and I want him to have a pleasant day at work. We don't talk about our religious stuff except rarely, and that's more when we are both having a great time as we really enjoy a good philosophical discussion. We can keep it non-confrontational and respectful because we have that kind of relationship. It's clear that this is a special relationship, and unlike the average interactions with people on the street or at work for instance.
I'm more than happy to wish someone a Merry Christmas, or Happy Channukah, even a Festive Saturnalia, because those things are important to them. If they wish it back to me, I don't take umbrage, I am actually perfectly okay with the positive wishes coming back to me.
Wow, I didn't mean to go on and on lol. SO...
tl;dr I'm good with it unless we are in a situation where I'm being asked my honest opinion.

A lot of different people say that nonsense for a great number of reasons. My response varies based on the who and the why.

Barf!

I just walk away. I'm not the jackass whisperer.

I was a "Believer" for most of my life till 5 years ago. If someone says this to me, in the event of my losing a near or dear one, I would explode.
But in a sensible manner, i should ask him/her about their qualifications, education or understanding on how It was meant to be or whether God has a will etc with a pure intent to humiliate them so that they learn a valuable lesson.(I wish i could say that). otherwise, i would turn a deaf ear or act as if i heard them - just not to hurt their feelings.

I don't have a reply - I listen, nod my head and then go about my way. I have no emotional reaction to that comment. One thing I've learned through this forum is that there are quite a few atheists that consider themselves superior over people of faith simply because they came to the right conclusion in terms of a creator and religion. However, these are also the most sensitive drama queens I've ever met in my life. "It was meant to be" or "Gods' will" are simply words - what happened to "sticks and stones will break my bones but names will never hurt me?" I'm a non-theist, I don't buy into any of that religious nonsense but my ego isn't so fragile that I become so easily offended by religious sentiment. I even bow my head when people around the dinner table say grace. I do this because it appears on the surface that I am respecting their customs but what they don't know is that while they are praying to their deity, I'm counting down the seconds until I can sink my teeth into some of the food on the table before me.

I find it really irritating. Sometimes I will say that I don't believe that. It depends on the setting.

I handle it in one of 3 ways. 1) Usually, I just ignore it. 2) I'll say " sometimes, bad things happen to good people" 3) if someone (usually a family member) is really forcing their beliefs on me, I'll say something to stop them like "telling me it's God's will, to me, is the same as telling me that Santa Clause made it happen."