Nowadays I believe strongly in the above caption :) In case of SMS, you really can't Identify the tone or pitch of the sender. There is always a possibility of taking it in different sense instead of the intended one. It depends on how the recipient reads it.
But I have observed such misunderstandings when people talk also. Few may feel that u r harsh.. for some others it may not be so. But I'm surprised how the speech/tone can be misunderstood!! I've experienced many such situations with myself. When this happens repeatedly, I tend to think I might be wrong. But I'll not get to know where I'm wrong!! I end up in a confusion :(
There might many such situations with u too.. How do u handle them? ( Without getting into confusion like me :P )