Making a common word or someone name like password,john,sarah is bad idea since anyone can workout that without having hacking knowledge overall.
Username and password is the same such as admin is very bad idea from a security viewpoint
Using same password in like 10 to 1000 sites is not a good idea every site account needs a different account if someone hacks your account or hacks a website connected to you if it was all the same password say skateboard then they could do a lot of damage to your details or make big purchases in your name some cases and be hard to get back from your bank unless you got a very good quality bank overall.
Having passwords like this can be a good idea
An average person can't remember this and a lot of software designed to crack passwords would struggle to solve the ones above in most cases and since they don't make sense so nothing for the software to apply logic to here overall.
You can use software to help remember passwords but be aware if they get hacked your account then all your details can be used or found out instant in some of the software we have found overall so keeping your password records offline can be a smart idea overall.