What will happen if I jailbreak my iPhone?

I heard that it messes with your warranty and stuff, but is it bad? I want to jailbreak my iPhone but I'm not sure what will happen.

Go right ahead. IPhones make elegant paperweights.

It will probably take it off warranty.

Provided you install from the official sources after jailbreak then nothing should happen. Make sure you jailbreak after the apple warranty is over.

Jailbreaking allows you to customize your phone in many ways that Apple has never allowed, nor will they ever do so.

With jailbreaking, you can download custom themes to make the phone look like an Android, Windows or Mac system. You can download files through Safari (not sure why Apple doesn't allow this natively), remove stock apps (like Stocks, Game Center, etc.) and many more things.

Of course, Apple doesn't like this at all, so they make it very difficult to jailbreak with every new version of iOS, plus your warranty is voided once you jailbreak.

However, if you restore your phone and take it to Apple, they won't know that it was jailbroken, as long as you don't tell them.

Some caution: Jailbreaking allows you to modify very deep files in iOS that were never meant to be user-accessible. It's unlikely (but possible) to permanently damage your phone. Don't do stupid things, like download cracked apps or use shady repos. Also, since none of these tweaks are approved by Apple, your phone might be less stable; more prone to crashes and lockups. Additionally, it is possible to get viruses that steal your information if you're not careful with what you download.