Well you’re used to writing “you” instead of “u” while texting (for the record, I also always write “you”). Similiarly, a lot of people (namely those who grew up with phones), are used to omitting full stops at the end of a message, so if someone does it it must be a conscious decision. See where I’m going with this? (Also it’s not like people who use them are immediately sounding passive-aggressive, context matters)