Seeking Perfection
As they say, things happen, so do bad joints. But no worries, get a solder pump or braided solder removal strip, and re-do the joint again. (Sorry I do not have a guide on using removal strips)
Bad connection shown in the right can really kill, it's not joining the 2 pieces together, and over time it'll fall off and leave you with problems that are difficult to find/solve. Excessive solder is okay, it works but doesn't look as good as a good joint, so let's call it a bad joint as well.
To clean off the solder, melt it with an iron. Leave the iron there, and while it's hot, put a solder pump up close and suck/release. Then you can start over again. Don't worry, the plastic on solder pumps are specially made and can handle some heat.
Alternatives includes de-soldering iron (basically just an iron with a metal tube connecting the tip and a sucker bulb), de-soldering braid (fine copper mesh wire that sucks liquid solder, single use)