Stealthy, am I not?

1. I once walked up behind my sister to her room, put my head beside hers while she was typing away at MSN. I watched her type for a minute or so, then I asked her something. She jumped.

2. I was walking behind a man downstairs of my block, and I had followed on his heels for about 10 metres or so. Upon reaching a short flight of stairs leading to the lift lobby, I impatiently stomped up the stairs. He quickly spun around and stepped aside, murmuring an apology.

3. I saw a cat lazing by the side of the pavement, eyes wide open. It was only when I reached an arms' length within it, did it quickly turn and realise I was so close. It bolted away.

However, the fat cat that lives 3 units away from me, same storey, can hear me 10 metres away. Normally when I see it, it is already looking at me.