Dont know if this is a common one but when I first starting running my nitro buggy I didnt install a failsafe. Thought to myself ah ill get one next week.

Long story short something interefered with signal and buggy took off at local car park while breaking in. Hit a curb at full pelt. Luckily the only thing that broke was steering servo horn.

I installed a failsafe the very next day along with a servo horn.