[Harv72b]

Cold-calling in limit hold'em is generally very bad. This is because either you have a worse hand than the raiser (and therefore do not have the proper pot odds to play your hand) or you have a better hand than the raiser (and therefore should be trying to get it heads up by re-raising). There are times when a coldcall is correct, usually in cases where the table is playing very loose and passive and/or several other players have coldcalled before you; in those cases coldcalling would be just fine with hands like small or mid pocket pairs or suited broadway cards, sometimes with smaller suited connectors as well. The reasoning being that while you may not have the immediate pot odds required to make your call, you are likely to win enough in implied odds (bets won on later streets) to make up for that when you flop big.

In no limit hold'em, flat calling a preflop raise is much more acceptable. The short version of why is that you can expect to win considerably more after the flop when you hit a big hand (or in some cases if you slowplay your big hand preflop).