A slow connection is a strategic mistake, where the player considers the connection to be important, i.e. if the connection is not played, the prospect of being cut is too severe, while either the groups connected are safe on their own, or one of them can be protected in a more profitable way. As such, the connection is slow.
reduces eye space at the left for the central white group, while making territory. can easily save her group by capturing 2 stones with . However this is a slow connection because Black can take the next big point at and turn the upper left into a big territory. White's development is not very efficient.
White's central group is stronger than it may look. It not only has a but also b and c. White has time to play in the upper left.
was a worthless cut. Worse, makes points and threatens to cut at a so Black will be forced to connect on a neutral point.