In brief, you will blow the engine.
If you run it too hot the engine will give out, and it will NOT work again. You're going to blow the motor, basically.
my car isn't steaming only in drive but not overheating.
I'm not positive about your car, or the dash setup, but generally a water light means your low on coolant. If you drive while low on coolant, you run the risk of overheating your engine. Obviously that's not a good thing.
You run out of your car and check if the person's dead. If he isn't, drive your car away as fast as you can. If he is dead, drive your car away even faster.
You can drive it till it blows up but my advice is to stop as soon as it starts overheating. it will probably seise up first so heed the above advise asap
a leak is probably getting on something hot and cooking away
pull over and call for help
If you drive a manual car your shifting isn't correct
It means that you engine is overheating. Check your water coolant level and oil levels. DO NOT continue to drive the car until the problem is resolved, an over hot engine will cease and after that happens you will need a new engine.
You shouldnt, the problem could be as simple as low coolant, a bad thermostat, or a clogged/dirtyradiator. All relatively easy fixes that will cost about $20 to take care of (if you do it yourself). Overheating your engine can damage it to the tune of a multi-thousand dollar repair or replacement.
You get arrested
you are most likely leaking coolant and if your car should be overheating in a short period of time.