does capitalization/grammar matter in office communications?

my supervisor brought up the fact that i never capitalize anything. well specifically i never capitalize i (typing that hurt my brain) i usually type all lower case because its faster and allows me to give a response quickly. i get how it can appear lazy but cant think of any other negative aspect of it. aannd just realized i sent another email without capitilizing anything to her out of force of habit and multitasking. so while i wait for that shitstorm to arrive...

what do you guys think of capilization and correct grammar in office communications (ie.texts,emails,post its)? is it just about getting the message across or does it reveal a persons nature?

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