It can be really hard to motivate yourself.
Your children might have a hard time getting that in your head you're at work when your body is at home which can be frustrating for everyone.
People call at weird hours even if you tell them not to.
It can get a little lonely, you might find that you miss the office.

On the positive side, you can call coffee break and wander off to the cafe whenever you want, enjoy some afternoon delight when the kids are at school/CC and cook dinner during your lunch break.

Motivation is the killer - like Sopdet said you need to get up and get dressed in work clothes so that in your head you're at work.