My Windows PC never crashed like my Macbook does.
And if it crashes for certain people chronically, then there's a syndrome that's reproducible. Meaning it is likely to affect a lot of people in similar circumstances.
The question is whether you can go from "2 or 3 friends of mine said they have more crashes than before" to "10.9.3 is more prone to crashing than 10.9.2." For all we know, the entire sample is using some 3rd party utility that crashes under the new update, which is bad, but is also not something you can completely blame Apple for.