I don't know about the Olympics, but for a WC I can hardly think of better country than Brazil (outside the top European countries-Germany, England, Italy, etc) to host a WC.
I don't mind their being selected to host a WC.. it seems a natural fit in terms of culture although there are obviously a lot of hurdles to overcome. I know they're having trouble getting all of the stadiums built though and some projections are suggesting they won't finish on time. Everyone is very nervous about the overwhelming amount of crime (or at least the stereotype of it) as well of course so it will be interesting to see how it turns out.
For them to get the 2014 WC and then be awarded the 2016 Olympics though was quite silly. The Olympics Committee should have seen how things went first. Ultimately, the US finished 4th in the 2016 voting despite Chicago being the favorite coming in to the day. Really makes no sense that we've been passed over so many times in recent years since the US is an obvious choice for any major event.
The Qatar thing was disgusting and corrupt though, no doubt about it.