Don't get me wrong. Brugge is lovely, but there are a few things that are a bit messed up. The sightseeing tours on a boat is one. I didn't think all of the boats look very safe. They are way too small considering how many people are in them and thinking about it, I'm not sure whether people were wearing life jackets. I was totally put off by them and would not recommend a boat tour even if you were an extremely good swimmer. The water is not that clean either..
All of the precinct areas in the town centre and most footpaths everywhere else are cobblestones. They do look nice but for people in wheelchairs or children in prams they must be awful. Also when wet they can be very slippery so beware.
People who are in some way physically impaired might find the cobblestones that pave some this ancient city's street rather uneasy to walk. Carefulness is advisable here, but shouldn't impede the impression these streets will inevitably leave.
Some Belgium Beer have an alcohol content of as high as 12% so watch out when you drink. You could have one too many , get loopy and fall into canal. I doubt you'll die since there will be enough sober tourists to rescue you but you'll embarrass your mate BIG TIME...
Other than Canals and Cobblestones, I think you ought to take note of the times when the BIG bell at the Belfry tower starts to chime.
I was unfortunately at the top when it happened. It was so not good for the olfactory system. I became slightly deaf for the whole day after that.
Don't fall in one of the many 'reien' (canals). If you don't drown, you will surely be hit by one of the tourist-boats. Do not jump of the Belfort either (it's over 100 mtrs high). (-: