TekSystems gave me an exploding offer, probably to discourage me from looking into other opportunities. The employment agreement was so bad (and violated state labor laws) that I walked away from that one quickly. On the other hand, my next employer, where I'm starting late next month, wanted to give me all the time I needed to consider the position: it requires self-management (rather than s boss telling you what to do) and a 2000 mile relocation.
Exploding offers are a bad "job smell."